Wiring Diagram

The LED VU meter is simpler and smaller than it's analogue counterpart, and is very common in audio equipment. This version is based on a National Semiconductor IC, and uses the logarithmic version. Each LED operates with a 3dB difference from the previous one, and a jumper is provided to allow dot or bar mode.

The circuit is completely conventional, and is based on the application notes from National Semiconductor. The circuit is shown picture below and as you can see it uses a single IC and a few discrete components. DC to the LEDs is almost unfiltered - C1 is included to make sure the IC does not oscillate, and is not a filter cap. This allows a higher LED current with lower dissipation than would be the case if the DC were fully smoothed, and full smoothing would also require a much larger capacitor. This increases the size and cost of the project - especially important if it is to be used in larger numbers as may be the case with a mixer or analyser.

USB can be configured for connecting several peripheral devices to a single PC, Since a PC can supply only a limited power to the external devices connected through its USB port, when too many devices are connected simultaneously, there is a possibility of power shortage, Therefore an external power source has to be added to power the external devices. In USB, two different types of connectors are used: type A and type B. The circuit presented here is an addon unit, designed to add more power to a USB supply line (type-A). When power signal from the PC (+5V) is received through socket A, LED1 glows, opto-diac IC1 conducts and TRIAC1 is triggered, resulting in availability of mains supply from the primary of transformer X1.

Now transformer X1 delivers 12V at its secondary, which is rectified by a bridge rectifier comprising diodes D1 through D4 and filtered by capacitor C2. Regulator 7805 is used to stabilise the rectified DC. Capacitor C3 at the output of the regulator bypasses the ripples present in the rectified DC output. LED1 indicates the status of the USB power booster circuit. Assemble the circuit on a generalpurpose PCB and enclose in a suitable cabinet.

Here is a series of Touch Switch using only 3 transistors, this touch-based transistor switches can activate a load simply by the user touching a metal plate. It is designed to directly switch a relay to allow it to be used with large loads. As it uses only a few commonly available transistors and a 12V supply, it is ideal for hostile environments where mechanical switches would be damaged. Using a latching relay and two of these circuits, a simple two pad "touch on / touch off" arrangement can be made.

The touch pad can be most easily made by cutting a small square of PCB material and then soldering on a single wire. Alternatively, something like a penny glued to a plastic backing will do the job.

This circuit will energize and de-energize a relay at the push of a button. Any type of momentary action push-to-make switch can be used. Pushing the button once - will energize the relay. And pushing it a second time - will de-energize the relay

I've drawn the circuit with a single pole relay. But you can use a multi-pole relay if it suits your application. Only one half of the Cmos 4013 is used. So you could construct two independent toggle switches with a single IC. The circuit will work at anything from 5 to 15-volts. All you need do is select a relay with a coil voltage that suits your supply.

The LED provides a visual indication that the relay is energized. In effect - it tells you whether the switch is on or off. It's not necessary to the operation of the circuit. If you wish you may leave out R3 and the LED.

At this thermometer circuit, the sensor (S8100) or diode (1S1588) is used as the thermo sensor. When using the IC thermo sensor, the thermometry to +100°C from -40°C is possible. Also, when using the diode, the measurement to +150°C from -20°C is possible. Both sensors are contained in the kit.

This time, the thermometer circuit used the diode as the thermo sensor to measure more than +100°C. ICL7136 is used for the thermometer and is measuring the change of the forward direction minute voltages of the diode by the temperature. The 3-1/2 digits liquid crystal display (SP521PR) is used for the display. The most significant digit can display only "1".

The consumption electric power of ICL7136 is very small and it is possible to operate about 3 months continuously with the 9-V cell.

Subwoofer controller is quite simple, an input buffer provides phase switching and ensures that the input impedance of the source does not affect the filter performance, and this is nowfollowed by a 12dB/octave high pass filter. The phase reverse switch is used so that the sub can be properly phased to the rest of the system. If the mid-bass disappears as you advance the level of control, then the phase is wrong, so just switch to the opposite position.Contribute a better translation

The board has only one input, so if you plan to use a normal stereo feed supplying a single P48 board, you'll need to sum the two stereo outputs. This is easily accomplished by using a pair of resistors - the value should be between 2.2k and 4.7k. If this is done, replace R1 with either a 100 ohm resistor or a wire link.

VR1 is used to change the gain of the second integrator. The level through the controller can be set to make sure that there is no distortion - there can be a huge amount of gain at low frequencies, and if the gain is too high, distortion is assured!

The high-pass filter is designed as a peaking type, and gives a response that is almost perfect down to 20Hz. The lowest frequency can be tailored by changing C1, C2, C3 and C4. As shown, the response peaks at 18Hz, but you can use 68nF to increase this to 27Hz, or 47nF for 39Hz. See Table 1 for the full range of values.

    * The STK4102II series (STK4192II) and STK4101V series (high-grade type) are pin-compatible in the output
    * range of 6W to 50W and enable easy design. Small-sized package whose pin assignment is the same
    * as that of the STK4101II series
    * Built-in muting circuit to cut off various kinds of pop noise
    * Greatly reduced heat sink due to substrate temperature 125°C guaranteed
    * Excellent cost performance

This circuit serves to show the speed of the vehicle in kmph. An opaque disc is mounted on the spindle attached to the front wheel of the vehicle. The disc has about equidistant holes on its periphery. On one side of the disc an infrared LED is fixed and on the opposite

side of the disc, in line with the IR LED, a phototransistor is mounted. IC LM324 is wired as a comparator. When a hole appears between the IR LED and phototransistor, the phototransistor conducts. Hence the voltage at collector of the phototransistor and inverting input of LM324 go ‘low’, and thus output of LM324 becomes logic ‘high’. So rotation of the speedometer cable results in a pulse (square wave) at the output of LM324. The frequency of this waveform is proportional to the speed.

This circuit can sense eight colours, i.e. blue, green and red (primary colours); magenta, yellow and cyan (secondary colours); and black and white. The circuit is based on the fundamentals of optics and digital electronics. The object whose colour is required to be detected should be placed in front of the system.

Note:

    * Potmeters VR1, VR2 and VR3 may be used to adjust the sensitivity of the LDRs.
    * Common ends of the LDRs should be connected to positive supply.
    * Use good quality light filters.

PISTOL MINIATURE ELECTROMAGHNETIC GUN CIRCUIT SCHEMATIC DIAGRAM

This is a miniature magnetic gun. when sakla 1 in press, it will propel a small slug about 1.5 meters high, 2.5 meters or horizontally. IC 555 is a timer in astable mode, sending approx. 10 ms pulses to decade counter IC2. IC2 is continually reset through R3, until pin 15 is taken low through the "Fire" button. IC2 then sequences through outputs Q1 to Q7, to feed power transistors TR1 to TR4, which fire electromagnets L1 to L4 in rapid sequence.

T1 is trafo step down 18 volts 1 amp A.C. When Rectified and smoothed, this provides 25.2 V DC for electromagnets L1 to L4. Resistors R4 drops 12 V to obtain a supply voltage low enough for IC1 and IC2.

The electromagnets are wound on a 25 cm long, 3 mm dia. copper tube (available at hobby shops). Two "stops" may be cut from tin for each electromagnet, and 500 turns of approx. 30 SWG. enamelled copper wire wound between them. The electromagnets should be wound on a base of sellotape reversed, so that one may slide them on the copper tube. The slug (or "bullet") is a 3 cm long piece of 2 mm dia. galvanized wire, which should slide loosely inside the copper tube.

Most Crucial to the effectiveness of the gun are the setting of VR1 and the positions of electromagnets L1 to L4 on the copper tube (the values and measurements shown are merely a guide). Firstly, with L2 to L4 disconnected, VR1 should be tuned and L1 positioned for optimum effectiveness (place a wire inside the tube to feel how far the slug jumps with L1). Then L2 (now connected) should be positioned for optimum effectiveness (the slug will now exit the tube). Repeat with L3 and L4.

Electronic devices should be powered by direct current supply DC (direct current) which is stable in order to work properly. The battery or batteries is a source of DC power supply is best. But for applications that require greater power supply, the source of the battery is not enough. Sources of power supply is a source of alternating AC (alternating current) from power plants. This requires a power supply device that can change the AC into DC current.

Now it should not need another effort to make good pwer supplay you do not need to look for op-amps, transistors and other components, because these circuits are packaged into a single fixed voltage regulator IC. Are now widely recognized as a component of 78XX series fixed positive voltage regulator and the 79XX series is a voltage regulator to remain negative. Even these components are usually already equipped with current limiting (current limiter) and also limiting the temperature (thermal shutdown). This component is only three pins, and by adding some components alone can be a series of power supply regulation was good.

Mice are wild animals and very annoying. "Action bawdy" it could be all kinds ranging from pooping everywhere, rummaging through closets and warehouses, spread diseases (plague), and so on. Just always make a scene! One alternative to overcome this is to use an electronic mouse repellent. In addition to environmentally friendly, this tool can also be used as a hobby and learning the distribution of electronics.

To drive these rats disorders, you can create an electronic circuit as shown below. This circuit will generate a 50Khz frequency disturbing enough for a mouse but you do not have worried because you will not hear it. This series is guaranteed by the rats would run because his ears will feel pain from the vibration signal ferkuensi.

In this section of talk about a type of insect repellent, insect repellant is a circuit that will repel insects from your home or yard with effectively. This circuit uses the frequency of bullying for the insect so the insect will go.

For this skesta insect repellent should be installed inside or outside the home can / for speaker. This series of in-circuit oscilator adl PLL circuit / phase looked loop by using a CMOS 4047 with frequency 22 khz.gunakan external power supply for better results.

This circuit measures the distance covered during a walk. Hardware is located in a small box slipped in pants' pocket and the display is conceived in the following manner: the leftmost display D2 (the most significant digit) shows 0 to 9 Km. and its dot is always on to separate Km. from hm. The rightmost display D1 (the least significant digit) shows hundreds meters and its dot illuminates after every 50 meters of walking. A beeper (excludable), signals each count unit, occurring every two steps.

Note:

    * Experiment with placement and sloping degree of mercury switch inside the box: this is very critical.
    * Try to obtain a pulse every two walking steps. Listening to the beeper is extremely useful during setup.
    * Trim R6 value to change beeper sound power.
    * Push P1 and P2 to reset.
    * This circuit is primarily intended for walking purposes. For jogging, further great care must be used with mercury switch placement to avoid undesired counts.
    * When the display is disabled current consumption is negligible, therefore SW3 can be omitted.

This circuit can be used for a headphone amplifier, arose after the purchase of commercial equipment with separate pre and power amplifiers without a headphone output. The intention is to permanently insert the headphone amp between pre and power amps. The gain control being used to pre-set the gain so that the pre-amp's gain control is normally used for setting the listening level.

Its advantages are :

    * low output impedance to drive several pairs of phones
    * The active gain stage is, almost, perfectly logarithmic and ...
    * Independent of the absolute value of the pot
    * Excellent channel tracking
    * O/P noise reduces with gain reduction.

The first stage is a conventional series feedback circuit using the ubiquitous NE5534, the gain being set by the feedback AOT (adjust on test) resistor to suit individual needs, this stage provides the necessary low impedance output for the variable gain stage. The resistor/ capacitor networks around the input stage may seem a little extravagant, but are necessary to reduce any possible RF pickup especially the 470 pF between the two IC + and - inputs.

This circuit will trigger a relay when a preset temperature is reached. The circuit uses a NTC thermistor with a resistance of 47k at room temperature. The circuit is set in balance by adjusting the the 47k Potentiometer. Any change in temperature will alter the balance of the circuit, the output of the op-amp will change and Energize the relay. Swapping the position of the thermistor and 47k resistor makes a cold or frost alarm.

At 25 degrees Celsius a NTC thermistor resistance is approximately 47k. The non-inverting op-amp inputs will then be Roughly half the supply voltage, adjusting the 47k pot should allow the relay to close or remain open. To calibrate the device, the thermistor Ideally needs to be at the required operating temperature. If this is for example, a hot water tank, then the resistance will decrease, one way to do this is use a multimeter on the resistance scale, read the thermistors resistance and then set the preset so that the circuit triggers at this temperature.

The following is a series of simple TV transmitter using negative using sound modulation and PAL video modulation. This is suitable for countries using TV systems B and G.

Inductor L1 can be made by wire email (24SWG) 4 convolution with 6mm diameter and T1 can be used with a radio frequency transformer internal capacitor. (Can be found on the old transistor radios).


List Componet of TV transmitter circuit

    * R1 = 10KOhm
    * R2 = 47KOhm
    * R3 = 15KOhm
    * R4 = 8.2KOhm
    * R5 = 47KOhm
    * R6 = 47KOhm
    * Variable resistor R7 = 1Kohm
    * R8 = 75Ohm
    * C1 = 10uF / capacitor 25Volt electrolik
    * C2 = 0.001uf / 10nF ceramic capacitor
    * C3 = 100nF
    * C4 = 10nf
    * C5 = 47pF (variable capacitors)
    * C6 = 10nF
    * C7 = 10pF
    * C8 = 27pF
    * C9 = 100nF
    * C10 = 470uF
    * C11 = 10nF
    * C12 = 220uF / 25Volt
    * Q1 = BC547 NPN transistor
    * Q2 = BC547 NPN transistor
    * T1 = T1 can use the radio frequency transformer with a built in capacitor. (Can be found on the old transistor radio board).
    * L1 = 4 turns of copper enamel 24SWG on 6mm diameter: with a plastic core

This is a circuit of sine wave oscillators covering a frequency range of 15 to 150kHz in four switched steps. Two conditions exist for a sinusoidal oscillator. Regenerative or positive feedback, and a closed loop gain of unity. The losses in the wien feedback circuit, are such that the open-loop gain of the amplifier must also exceed 3.

The circuit gain is provided by a FET type op-amp (LF351), but LF351 may be difficult to obtain, for a replacement you can use TL071CN or TL081CN. The Maplin order codes are RA67X and RA70M respectively. The wien network is a parallel combination of resistors and capacitors, in series with a series RC network. Regenerative feedback is applied from the op-amp output, to the serail RC input and continues. Stabilization is required to prevent the otherwise Uncontrolled oscillation from building up and becoming unstable.

This is circuit for accurate time-base generation using the readily available 3.5795MHz crystal commonly used in telecommunication equipment. Crystal-based oscillator with divider IC chain or a similar circuit in the form of an ASIC is used for time-base generation. The 3.5795MHz crystal is used in conjunction with a CD4060-based crystal oscillator- cum-divider (IC1). The crystal frequency is divided by 512 by IC1, which is further divided by 7 by CD4017 (IC2). IC2 is reset as soon as its Q7 output goes high.

Thus the crystal frequency is divided by 3584, giving the final output frequency of around 998.8 Hz. This frequency can be trimmed to exactly 1 kHz with the help of trimmer capacitor VC1 as shown in the figure. The 1kHz signal can be further divided using decade counters to generate the required time period. EFY lab note.

This is the circuit of Op-Amp Microphone Preamplifier using a single power supply, this circuit suitable for dynamic or electret microphones. Nothing too special here. The Schematic is shown using a dynamic microphone, for use with an electret a pair of suitable biasing resistor is required to power the electret microphone.

rangkaian Op-amp pre-amp micSkema rangkaian op-amp pre-amp mic

Note:

    * use a capacitor with voltage 25volt or more
    * so that the sound produced maximal use supplay good voltage, with output of 18 volts max
    * If the desired strengthening of the different, you can change the value of R1 or R2


The design is a standard non-inverting design, the input is applied to the non-inverting input of the op-amp, which is pin 3 in most cases. The input impedance is 23.5k, the overall voltage gain is determined by R2 and R1according to the following formula:

Vo = (R2 / R1) + 1

With the values of R2 and R1 on the diagram of the voltage gain (for mid band, 1kHz) is approximately 23x or 27.2dB.

This circuit is IC controlled emergency light. This series of automatic switching-on of the light on mains failure and battery charger with overcharge protection. When mains is absent, the relay RL2 is in deenergised state, feeding battery supply to the inverter section via its N / C contacts and switch S1.

The inverter section comprises IC2 (NE555) which is used in a stable fashion to produce sharp pulses at the rate of 50 Hz for driving the MOSFETs. The output of IC3 is fed to the gate of MOSFET (T4) directly while it is applied to MOSFET (T3) after inversion by gate transistor T2. Thus the power amplifier built around MOSFETs T3 and T4 functions in push-pull mode. The output across the secondary of transformer X2 can easily drive a 230-volt, 20-watt fluorescent tube. In case light is not required to be on during mains failure, simply flip the switch S1 to off position. Battery overcharge preventer circuit is built around IC1 (LM308). Its non-inverting pin is held at a reference voltage of approximately 6.9 volts which is obtained using diode D5 (1N4148) and 6.2-volt zener D6.

To get good audio reproduction at different listening levels, a different tone-setting controls should be necessary to suit the well known behavior of the human ear. In fact, the human ear sensitivity varies in a non-linear manner through the entire audible frequency band, as shown by Fletcher-Munson curves.

A simple approach to this problem can be done inserting a circuit in the Preamplifier stage, capable of automatically varying the frequency response of the entire audio chain in respect to the position of the control knob, in order to keep ideal listening conditions under different listening levels .

Fortunately, the human ear is not too critical, so a rather simple circuit can provide a Satisfactory performance through a 40db range.

In the world of electronics using crystal oscilator almost always in use. In the circuit below is a series to test the crystal. (Not measuring frequensy). With this circuit we could find out whether the crystal is still good or not. Test Clip to attach electrodes on crystal (foot), S1 in the press (On) then LED1 will light up if the crystal is still good. if you mendapa difficulties 2N356U transistors can be used with the type of transistor NTE123AP / PN100 / 2N3904.

The mechanism of this crystal tester is very simple. If a good crystal is connected to the test lead, the oscillator will work, and an AC signal will be generated at Q1 emitter. This AC signal will flow through capacitor C3 and trigger the Q2 to light the LED indicator. The diode 1N4148 provide the back path for the AC signal. If the crystal is bad, the oscillator won’t work, and there is only DC voltage level at Q1 emitter. This DC voltage level won’t trigger the Q2 transistor since the capacitor C3 block any DC signal. You can use any high gain high frequency transistor for this crystal tester circuit, in case you can’t find exact transistor series as shown in the schematic diagram.

The following is a circuit that can be used to control the dc motor rotation direction. S1 and S2 are normally open, push to close, press button switches. The diodes can be red or green and are there only to indicate direction. You may need to alter the TIP31 transistors depending on the motor being used. Remember, running under load Draws more current.

This circuit was built to operate a small motor used for opening and closing a pair of curtains. As an advantage over automatic closing and opening systems, you have control of how much, or how little light to let into a room. The four diodes surriunding the motor, are back EMF diodes. They are chosen to suit the motor. For a 12V motor drawing 1amp under load, I use 1N4001 diodes.

Circuit of cable tester with a separate LED Will show open circuits, short circuits, reversals, earth faults, continuity and all with four IC's. The circuit comprises transmitter and receiver, the cable under test linking the two. The transmitter is nothing more than a "LED chaser" the 4011 IC is wired as astable and clocks a 4017 decade counter divider. The 4017 is arranged so that on the 9th pulse,the count is reset. Each LED will light sequentially from LED 1 to LED 8 then back to LED 1 etc. As the 4017 has limited driving capabilities, then each output is buffered by a 4050. This provides sufficient current boost for long cables and the transmitter and receiver LED's. The receiver is simply 8 LED's with a common wire.

This is a circuit that serves to indicate various levels of hot water in a tank. SW1 is a normally open press button switch which allows you to view the level of hot water in a hot water tank. When pressed the voltage difference at the junction of the thermistor and preset is compared to the fixed voltage on the op-amps non-inverting input. Depending on the heat of the water in the tank, the thermistors resistance will toggle the op-amp output to swing to almost full voltage supply and light the appropriate LED.

Note:

    * Op-Amp: LM324 or any quad opamp can be used or even four single op-amps.
    * R2-R5: 330ohm resistors, but Lower values give brighter LED output.
    * NTC1-4: Cold resistance was around 300K, hot resistance 15k. Alternative thermistors may be used with different resistance ranges, but the presets P1 to P4 must also be changed as well.
    * R7-10: only required if your thermistors resistance is several ohms at the hottest temperature.
    * P1 - P4: Chosen to match the resistance of the thermistor when cold.
    * R1 & R6: 100k Resistor


Masking tape was used to stick the bead thermistors to the tank. Wires were soldered and insulated at the thermistors ends. A plastic box was used to house the circuit. Battery life will probably be 4 to 5 years depending on how often you use the push switch, SW1.

This is the circuit of guitar reverb circuit, it is suitable for use as a front-end to a guitar amplifier. This circuit features clipping indicators on the preamp and reverb recovery stages, allowing for the optimal gain settings.
Specifications

rangkain gitar reverb efekSkema rangkain gitar reverb efek


The guitar input stage is a class A amplifier with adjustable bias. A 2N3906 PNP tranistor is used for a low noise design on this stage. The output of the preamp stage is sent to three places: the output mixer amp, the reverb driver amp, and the input clipping detector.

The reverb driver amp consists of a phase inverting push-pull circuit made from dual sections of a 5532 high quality audio op-amp. This provides a voltage swing of approximate twice the supply voltage to the reverb impedance matching transformer, allowing higher power transfer. The 100 ohm resistor is critical for insuring a clean drive signal, without it, the op-amps can saturate when driving the transformer, producing unwanted distortion.

For you who like to assemble their own or following electronic love is one of a series of simple Treble Booster

Treble Booster seldom used by guitarists, and if the only digunakanpun final choice, but there are also still likes the sound of guitar effects "Treble Booster" Screaming Bird Treble Booster was first introduced by the Electro-Harmonix was the era when 70 -- the company is producing guitar effects Screaming Bird Treble Booster. And in this current era of emerging many similar effects in treble booster which sell in the market, either a modified or an almost similar to the original sound.

rangkaian efek gitarSkema rangkaian efek gitar

Transistor 2n5133 is difficult to find in the market, these transistors are short data


Various
Si NPN Lo-Pwr BJT
V(BR)CEO (V)=18
V(BR)CBO (V)=20
I(C) Abs.(A) Collector Current=50m
Absolute Max. Power Diss. (W)=200m
I(CBO) Max. (A)=.05u
f(T) Min. (Hz) Transition Freq=40M
Package=TO-106
Military=N

This is an efficient flyback driver for modern cylindrical rectified television flybacks. Frequency range can be increased using multiposition switch for other values of C3 capacitor, for example 2 nF for 80KHz-200000KHz, but didn't found flybacks with so high resonant frequencies, in addition with higher values of c3 , eg 200nF, 2uF the frequency will drop making possible the use of ignition coils, and rectified power transformers @50Hz to charge high voltage electrolitic caps at 300-400V).

rangkaian driver (penggerak) playback TVSkema rangkaian driver (penggerak) playback TV


The 555 is wired as an astable and the capacitor is charged only through the 4,7Kohm trimmer (notice the diode) and discharged only through the 2.2 Kohm trimmer, making the duty cycle full adjustable. The square wave is then feed in a totem pole made up of a 2N3904 and a 2N3906, which are cheap, and easy to find. The totem pole ensures the gate being charged and discharged very fast (approx 50nS). The IRF840 is a cheap reliable and powerful power mosfet, it has current capability of 8 A continuous and 32A pulse, 800V drain source voltage, protecting internal zener diode. There is a snubbing network to ensure that voltage spikes are kept low (unless the insulation of the transformer start to leak) protecting both transistors and 555 IC. 100 ohm is a compromise between decay time and voltage spike.

The following circuit of special functions to detect the presence or absence of signal AF / RF. This circuit is very simple so as to make it requires a relatively low cost. Detektor Signal AF/RF circuit based an audio amplifier and a loudspeaker with a switch input to the AF and RF signal. The whole device can be made as small as possible so that it can be included in a container to keep the peace.

Audio amplifier section in this series created by IC TDA 2822M, with a low-power stereo amplifier in 8-pin mini-DIP. This IC is used as a bridge cofiguration to minimize output power up to 250 mW, the loudspeaker is in use 4 ohm, 500mW. Current required is less than 10mA with a 3V battery voltage.

SIMPLE DELAY SPEAKER CIRCUIT SCHEMATIC DIAGRAM

This is scircuit which I built to one of audio amplifier projects to control the speaker output relay. The purpose of this circuit is to control the relay which turns on the speaker output relay in the audio amplifier. The idea of the circuit is wait around 5 seconds ofter the power up until the spakers are switched to the amplfier output to avoid annoying "thump" sound from the speakers. Another feeature of this circuit is that is disconnects the speaker immdiatly when the power in the amplifier is cut off, so avoinding sometimes nasty sounds when you turn the equipments off.

Then power is applied to the power input of the circuit, the positive phase of AC voltage charges C1. Then C2 starts to charge slowly through R1. When the voltage in C2 rises, the emitter output voltage of Q1 rises tigether with voltage on C2. When the output voltage of Q2 is high enough (typically around 16..20V) the relay goes to on state and the relay witches connect the speakers to the amplifier output. It takes typically around 5 seconds after power up until the relay starts to condict (at absolute time depends on the size of C2, relay voltage and circuit input voltage).

CONTROL RELAY WITH INFRARED CIRCUIT SCHEMATIC DIAGRAM

Normally, home appliances are controlled by means of switches, sensors, etc. However, physical contact with switches may be dangerous if there is any shorting. The circuit described here requires no physical contact for operating the appliance. You just need to move your hand between the infrared LED (IR LED1) and the phototransistor (T1).

The infrared rays transmitted by IR LED1 is detected by the phototransistor to activate the hidden lock, flush system, hand dryer or else. This circuit is very stable and sensitive compared to other AC appliance control circuits. It is simple, compact and cheap. Current consumption is low in milliamperes. The circuit is built around an IC CA3140, IRLED1, phototransistor and other discrete components. When regu lated 5V is connected to the circuit, IR LED1 emits infrared rays, which are received by phototransistor T1 if it is properly aligned. The collector of T1 is connected to non-inverting pin 3 of IC1. Inverting pin 2 of IC1 is connected to voltage-divider preset VR1. Using preset VR1 you can vary the reference voltage at pin 2, which also affects sensitivity of the phototransistor. Op-amp IC1 amplifies the signal received from the phototransistor. Resistor R3 controls the base current of transistor BC548 (T2). The high output of IC1 at pin 6 drives transistor T2 to energise relay RL1 and switch on the appliance, say, hand dryer, through the relay contacts. The working of the circuit is simple.

CONTROL MOTOR STEPPER CIRCUIT SCHEMATIC DIAGRAM

The circuit is very simple and inexpensive. This is good thing because most commercial stepper motor controller ICs are quite expensive. This circuit is built from standard components and can easily be adapted to be controlled by a computer. If you use cheap surplus transistors and stepper motor, the price of the circuit can be kept to under $10.

Note:
You should be able to substitute any standard (2N3055, etc.) power transistor for Q1-Q4.
Every time the STEP line is pulsed, the motor moves one step.
S1 changes the motors direction.

BOOSTER RADIO FM SCHEMATIC CIRCUIT DIAGRAM

Here is a simple circuit of an FM booster that can be used to listen to programmes from distant FM stations clearly. This amplifier will pull in all distant FM stations clearly. The circuit is configured as a common-emitter tuned RF pre-amplifier wired around VHF/UHF transistor Q1.

rangkaian boster radio penerima FM
Skema rangkaian boster radio penerima FM


2SC2570. (Only C2570 is annotated on the transistor body.) Assemble the circuit on a good-quality PCB (preferably, glass-epoxy). Adjust input/ output trimmers (VC1/VC2) for maximum gain.

SIMPLE BOOSTER TV SCHEMATIC DIAGRAM

This is circuit that can be used to strengthen the RF signals from a television antenna work at UHF frequencies in the range 450-800MHz. It has a gain of around 10dB and is suitable for boosting weak TV signals

The tuned circuit comprising the 15nH inductor and 2.2pF capacitor resonate in the center of the UHF band. The 2.2pF capacitor may be Exchanged for a 4.7pF or a Trimmer capacitor of 2-6pF to improve results. The approximate frequency response is shown below. N.B. This is a simulated response using the TINA program produced by using a swept input 20uV swept over the frequency range 400-800MHz. Output was measured into a 1k source and the frequency generator has a 75ohm impedance.

BASS-TRABLE AUDIO TONE CONTROL SCHEMATIC DIAGRAM

This is a simple tone control can be used in may audio applications. It can be added to amplifers, used as a stand alone control module, or even built into new and exciting instruments. It's one IC construction makes it a very compact circuit, as only a few support components are required. Plus, it does not use a dual power supply. This means that the circuit will run from 9V to 15V (although the bass will be a little weak at 9V).

IC LM1036 is controlled tone (bass/treble), volume and balance circuit for stereo applications in car radio, TV and audio systems. An additional control input allows loudness compensation to be simply effected. Four control inputs provide control of the bass, treble, balance and volume functions through application of DC voltages from a remote control system or, alternatively, from four potentiometers which may be biased from a zener regulated supply provided on the circuit. Each tone response is defined by a single capacitor chosen to give the desired characteristic.

AUDIO TONE CONTROL 2 TRANSISTOR CIRCUIT SCHEMATIC DIAGRAM

Audio tone control circuit based transistors on these provides a maximum cut and boost of around 10dB at 10K and 50Hz.
audio tone control 2 transistorSkema rangkaian audio tone control 2 transistor


The first BC109C transistor is acting as a buffer. It provides the circuit with a high input impedance, around 250k has a voltage gain of slightly less than unity. As the Baxendall tone control circuit is a passive design, all audio frequencies are attenuated. The position of the controls and reactance of the capacitors alters the audio response. The last transistor provides a slight boost of about 3x. The output is designed to feed an amplifier with input impedance of 10k to 250k. Both tone controls should be linear type Potentiometers.


quick Data Transistor BC109C

Low current max. 100 mA
Low voltage max. 45 V
Collector-base voltage open emitter 30 V
Collector-emitter voltage open base - 20 V
Peak collector current - 200 mA
total power dissipation Tamb £ 25 °C - 300 mW
DC current gain (hFE ) IC = 2 mA; VCE = 5 V 200 - 800
transition frequency IC = 10 mA; VCE = 5 V; f = 100 MHz 100 - MHz

AUDIO LIMITER BERBASIS OP-AMP CIRCUIT SCHEMATIC DIAGRAM

This audio peak limiter employs a FET as a variable resistance to attenuate the input signal according to a control voltage (CV). It offers unusually good performance with low cost and component count. A TL072 dual opamp (U1) provides the circuit gain and full wave peak detection.


Audio Limiter Berbasis Op-AmpSkema Rangkaian Audio Limiter Berbasis Op-Amp


If desired, a LED VU meter may be used here instead, and with proper calibration will give a good indication of the peak attenuation at any time. This option will require some experimentation from the constructor, and further details are up to the individual to work out.

The 4.7K resistor and 1uF capacitor (R14 and C5) determine the attack time, which is about 5ms as shown. R12 and C5 determine the release or recovery time, and as shown this is approximately 1 second.

R11, C3 C4 and R13 form the distortion cancelling circuit, and as can be seen, the control voltage impedance is very low compared to the distortion cancellation impedance, so the circuit's attack time is not compromised. The values of resistance and capacitance have been optimised for the least distortion across the audio band, at 0.3% THD typical for frequencies above around 500 Hz, at 1.65V RMS output level. Below 500 Hz, the distortion rises gently with decreasing frequency, but also falls with lower voltages. Distortion is negligible at any voltage level below the limiting threshold.

AMPLIFIER MOSFET 60WATT SCHEMATIC DIAGRAM

The following is a 60 - 90W High Quality power amplifier. Circuit topology is about the same of the above mentioned amplifier, but the extremely IRFP9240 Rugged IRFP240 MOSFET devices and are used as the output pair, and well Renowned high voltage Motorola's transistors are employed in the preceding stages. The supply rails prudentially voltage was kept at the rather low value of + and - 40V. For those wishing to experiment, the supply voltage rails could be raised to + and - 50V maximum, allowing the amplifier to approach the 100W into 8 Ohm target

Rangkaian 60watt Amplifier Mosfet
Skema Rangkaian 60watt Amplifier Mosfet

Note:

    * A small, U-shaped heatsink must be fitted to transistor Q6 & Q7.
    * Mosfet Q8 & Q9 must be mounted on large heatsinks.
    * Quiescent current can be measured by means of an Avo-meter wired in series to the positive supply rail and no input signal.
    * Set the Trimmer R10 to its minimum resistance.
    * Power-on the amplifier and adjust R10 to read a current drawing of about 120 - 130mA.
    * Wait about 15 minutes, watch if the current is varying and readjust if necessary.

This circuit emits a beep and/or illuminates a LED when someone touches the door-handle from the outside. The alarm will sound until the circuit will be switched-off.

Q1 forms a free-running oscillator: its output bursts drive Q2 into saturation, so Q3 and the LED are off. When part of a human body comes in contact with a metal handle electrically connected to the wire hook, the body capacitance damps Q1 oscillations, Q2 biasing falls off and the transistor becomes non conducting. Therefore, current can flow into Q3 base and D3 illuminates. If SW1 is closed, a self-latching circuit formed by Q4 & Q5 is triggered and the beeper BZ1 is activated.When the human body part leaves the handle, the LED switches-off but the beeper continues to sound, due to the self-latching behavior of Q4 & Q5. To stop the beeper action, the entire circuit must be switched-off opening SW2. R3 is the sensitivity control, allowing to cope with a wide variety of door types, handles and locks.

500Watt Power Amplifier

There are some important updates to this project, as shown below. Recent testing has shown that with the new ON Semi transistors it is possible to obtain a lot more power than previously. The original design was very conservative, and was initially intended to use 2SA1492 and 2SC3856 transistors (rated at 130W) - with 200W (or 230W) devices, some of the original comments and warnings have been amended to suit.


Rangkaian 500Watt Power Amplifier Skema Rangkaian 500Watt Power Amplifier

Note:

    * This amplifier is not trivial, despite its small size and apparent simplicity. The total DC is over 110V (or as much as 140V DC!), and can kill you.
    * The power dissipated is such that great care is needed with transistor mounting.
    * The single board P68 is capable of full power duty into 4 Ohm loads, but only at the lower supply voltage.
    * For operation at the higher supply voltage, you must use the dual board version.
    * There is NO SHORT CIRCUIT PROTECTION. The amp is designed to be used within a subwoofer or other speaker enclosure, so this has not been included. A short on the output will destroy the amplifier.

12VDC FLUORESCENT LAMP DRIVER SCHEMATIC DIAGRAM

Whenever there is a need for battery-powered lighting, like for camping, solar powered cottages, cars, boats, planes, or emergency purposes, fluorescent lamps have a great appeal. Firstly, they are very much more efficient than glow lamps, so they produce much more light for less power consumption. Secondly, their light color stays constant while the battery runs down.

In this article I will offer driver circuit for 12 V/5Watt fluorescent lamp, this circuit used a normal 220 to 10V stepdown transformer in reverse to step 12V to about 240V to drive a lamp without the need to warm the filaments.
Rangkaian 12VDC Fluorescent Lamp DriverSkema Rangkaian 12VDC Fluorescent Lamp Driver

The IC1 TLC 555 is wired as an astable multivibrator for producing the necessary oscillations.The MOSFET Q1 is used to amplify the oscillations produced by the IC1.The out put of MOSFET is connected to the primary of the step up transformer to produce a ~240 V AC for driving the florescent lamp.

List Component:

    * C1 100uf /25V Electrolytic Capacitor
    * C2,C3 100nf Ceramic Capacitor
    * C4 100nf /1KV Ceramic Capacitor
    * R1 1K Resistor
    * R2 2.7K Resistor
    * Q1 IRF510 MOSFET
    * U1 TLC555 Timer IC
    * T1 300mA, 10V/220v Transformer
    * LAMP 5W Fluorescent Lamp
    * MISC Board, Wire, Heatsink For Q1

8WATT AUDIO AMPLIFIER TDA2030 CIRCUIT SCHEMATIC DIAGRAM

This is a circuit of 8-watt audio amplifier IC TDA2030-based mono. When you use 4 ohm speakers then you get 14 watts output power, and around 8 watts if you use 8 ohm loudspeaker.

Although the TDA2030 is capable of delivering 20 watts of audio power, I deliberately reduced the output to about 8 watts to 10 watts drive speakers. This is more than adequate for a smaller room. Input sensitivity is 200mV. Higher input levels naturally will give greater output, but no distortion should be heard. The gain is set by the 47k and 1.5k resistors. The TDA2030 IC is affordable and makes a good replacement amplifier for low to medium audio power systems. Incidentally, it is speaker efficiency that determines how "loud" the sound is. Speaker efficiency or sound pressure level (SPL) is usually quoted in dB / meter. A speaker with an SPL of 97dB / m will sound louder than a speaker with an SPL of 95dB / m.

Absolute Maximum Ratings IC TDA2030

Supply voltage ± 18 (36) V
Input voltage Vs
Differential input voltage ± 15 V
Output peak current (internally limited) 3.5 A
Power dissipation at Tcase = 90°C 20 W
Tj Stoprage and junction temperature -40 to 150 °C

BASIC POWER AMPLIFIER IC LM12 CIRCUIT SCHEMATIC DIAGRAM

This is 80Watt power amplifier OCL circuit using devices pillar is the integrated circuit LM12. This interesting routes many good bass and treble alive. If a friend is the CD therefore has a beautiful voice and Pre Tone Control is good that some will take something very magical. Importantly should choose Power supply source, which has been fairly high voltage class 38Vdc GND 38V-3A is the current low level. To decorate the fines resulting from the size finely R4 2 ohm/4W Idle current about 30mA, or with the whole center just before. Almost forgotten friends should choose the material is good, good, especially IC LM12 and Transistor everyone.

PENGUKUR SUARA SPEAKER SCHEMATIC DIAGRAM

This circuit can be used to setup their home-cinema set adjusting all the loudspeaker outputs to the same level when heard from the listening position. The circuit is very simple (though linear and precise) ac millivoltmeter, using an existing multimeter set to 50 or 100µA fsd with the probes connected to J1 and J2 to read the results.

Control | Pengendali Relay Menggunakan Transistor

The following series of functions to control the relay kutup. With an input signal greater than 0.3V pk-pk (100mV RMS) the positive half of the waveform will switch on transistor Q1, and Q2 and the relay. As the input signal switches to its negative transition, Q1 will switch off, but the base current in using-multimeter-to-measure-transistor.html">transistor Q2 continues to flow via the C2, so Q2 and hence load relays remain on. This will happen for any ac signal within 50 to 1000Hz. R1 prevents excessive base current flowing in transistor Q2, if required a series resistor of 100 ohms can be included with C1 to reduce excessive current flow, though this may decrease sensitivity.

C2 has a dual purpose; as well as smoothing the input signal, it adds a delay to the on / off operation. The delay is dependent on the value of C2 and the coil resistance of the relay. Instead of a relay, a LED and series resistor of 1k could be used instead, however the relay has the advantage of being able to switch large loads on and off. C2 has a dual purpose; as well as smoothing the input signal, it adds a delay to the on / off operation.

OP-AMP FOR PEMBANDING TEGANGAN CIRCUIT DIAGRAM

This following project serves to compare whenever the input voltage differs from two defined limits, V1 and V2. This circuit will provide an indication whenever the input voltage differs from two defined limits, V1 and V2. The supply voltage, Vcc must be higher than the highest input voltage by at least 2 volts. One application here is to monitor a 12V car battery. V1 could be set to 14V and V2 to 11V thus giving an indication of over charge or a weak battery.

The CA3140 op-amps are used to advantage as they have very little output offset voltage and can switch down to near 0volts. If any other op-amp is used such as CA741 or LF351 then it will be necessary to have an offset null control. This is just a 10k preset pins contacted between 1 and 5, the wiper connected to the negative supply rail op-amps or 4 pins.

MICROPHONE COMPUTER CIRCUIT SCHEMATIC DIAGRAM

The sound card for a PC generally has a microphone input, speaker output and sometimes line inputs and outputs. The mic input is designed for dynamic microphones only in impedance range of 200 to 600 ohms. Lazar has adapted the sound card to use a common electret microphone using this circuit. He has made a composite amplifier using two transistors.

rangkaian microphone komputer Skema rangkaian microphone komputer

Transistor BC413B operates in common emitter to give a slight boost to the mic signal. This is followed by an emitter follower stage using transistor BC547C. This is necessary as the mic and circuit and battery will be some distance from the sound card, the low output impedance of the circuit and screened cable ensuring a clean signal with minimum noise pickup.

Transistor BC413

    * Collector Emitter Voltage VCEO 30 V
    * Collector Base Voltage VCBO 45 V
    * Emitter Base Voltage VEBO 5.0 V
    * Collector Current Continuous IC 100 mA
    * Power Dissipation at Ta=25ºC PD 350 Mw Derate Above 25ºC 2.8 mW/ºC
    * Power Dissipation at Tc=25ºC PD 1.0 W Derate Above 25ºC 8.0 mW/ºC
    * Operating and Storage Junction TJ, Tstg ºC - 55 to +150

SKEMA RANGKAIAN PENENTU B-C-E TRANSISTOR

Basis-Collector-Emitter Transistor

Testing procedure:

    * Connect randomly the pins of the transistor under test to J1, J2 and J3 sockets or clips.
    * Close SW1, SW2 and SW3.
    * Push on P1; if the transistor is in good health the response of the Identifier will be:
    * Two terminals will show both LEDs illuminated, the remaining one will show a single LED illuminated.
    * If the LED illuminated is Red, the pin connected to the related connector will be the Base of a NPN transistor.
    * If the LED illuminated is Green, the pin connected to the related connector will be the Base of a PNP transistor.
    * Open the switch related to the single illuminated LED: the two terminals showing both LEDs illuminated will change their state and a single LED per terminal will be illuminated. The LED which previously indicated the Base pin will turn-off.
    * If the transistor was previously identified as NPN, the pin connected to the now illuminated Green LED will be the Emitter, whereas the pin connected to the Red LED will be the Collector.
    * If the transistor was previously identified as PNP, the pin connected to the now illuminated Red LED will be the Emitter, whereas the pin connected to the Green LED will be the Collector.

LED INDICATOR AUDIO AMPLIFIER CIRCUIT SCHEMATIC DIAGRAM

This circuit, connected to the loudspeaker output of an audio amplifier, will indicate the instantaneous output power delivered to the loudspeaker(s) by means of six LEDs illuminating one after another by voltage values increasing little by little, providing the visual impression of a luminous bar or column, increasing and decreasing in height following the increase and decrease of the signal’s level.

Notes:

    * The output power indicated by each LED must be doubled when 4 Ohms loads are driven.
    * The circuit can be adapted to suit less powerful amplifiers by reducing the number of LEDs and related voltage dividers.