Friday, November 2, 2012
A Small project on Battery level Indicator
Working principle of this circuit is battery voltage compared with the reference voltage. This circuit is constructed by using 741 op-amp ICs. Op-amp is differential amplifier which output will be positive or negative, depends on the difference of input voltages.
When the input voltage difference is positive with respect to reference voltage and battery voltage, then the output is positive and the LED will emit light. If negative LED cannot emit light. It is the main principle of battery level indicator.
Voltage level indicated by the column of LEDs. For easy of reading LED rearranged in a vertical array.
The top four LEDs indicates the battery voltage is high. Sequentially the lower level indicates the battery voltage is low and bottom four LEDs indicates very low voltage of the battery. So, if the battery voltage continues to decline then LEDs will die in sequence from top to bottom. In this circuit 1mA current is adjusted for reference voltage. Vcc is divided by the total number of resistor for finding the value of resistor R. On the other hand, the resistor value of R1 is calculated by the equation,
Component:
1. Op-amp IC 741
2. R = 3kΩ
3. R1 =220kΩ
4. Diode
Operation:
The voltage drop against the each resistor is 3 volt.
So when the Vin = 0v or less than 3v the output of all op-amp are at
–Vsat . The silicon diodes protect the light emitting diodes against excessive reverse bias voltage.
When Vin is increased to a value 3v to 6v, only the output of op-amp#1 goes positive to light which indicate “Very Low”.
When Vin is increased to a value 3v and 6v, the output of op-amp#1 and op-amp#2 are at +Vsat and goes positive to light which indicate “Low”.
When Vin is increased to a value 6v and 9v, the output of op-amp#1, op-amp#2 and op-amp#3 are at +Vsat and goes positive to light which indicate “Medium”.
Similarly, when Vin increased to 12v or higher, the output of all op-amps are at +Vsat and all op-amps output goes positive to emit light of all LEDs which indicate “Full” .
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The top four LEDs indicates the battery voltage is high. Sequentially the lower level indicates the battery voltage is low and bottom four LEDs indicates very low voltage of the battery. So, if the battery voltage continues to decline then LEDs will die in sequence from top to bottom. In this circuit 1mA current is adjusted for reference voltage. Vcc is divided by the total number of resistor for finding the value of resistor R. On the other hand, the resistor value of R1 is calculated by the equation,
Component:1. Op-amp IC 741
2. R = 3kΩ
3. R1 =220kΩ
4. Diode
Operation:
The voltage drop against the each resistor is 3 volt.
So when the Vin = 0v or less than 3v the output of all op-amp are at
–Vsat . The silicon diodes protect the light emitting diodes against excessive reverse bias voltage.
When Vin is increased to a value 3v to 6v, only the output of op-amp#1 goes positive to light which indicate “Very Low”.
When Vin is increased to a value 3v and 6v, the output of op-amp#1 and op-amp#2 are at +Vsat and goes positive to light which indicate “Low”.
When Vin is increased to a value 6v and 9v, the output of op-amp#1, op-amp#2 and op-amp#3 are at +Vsat and goes positive to light which indicate “Medium”.
Similarly, when Vin increased to 12v or higher, the output of all op-amps are at +Vsat and all op-amps output goes positive to emit light of all LEDs which indicate “Full” .
Tuesday, October 9, 2012
Monday, September 17, 2012
Ceiling Fan Regulator - Motor Speed Control Circuit Diagram
This is a simple ceiling fan regulator circuit diagram. It is used to control the speed of a ceiling fan. In the other words it is an AC motor speed controller circuit, as because it's control the speed of a AC motor(Ceiling Fan). This ceiling fan regulator circuit built with few numbers of parts. The circuit mainly based on Z0607 TRIAC. This is a low power AC semiconductor device. Generally which is used to controlling speed of low power ac motor speed.
Circuit Diagram of Ceiling Fan Regulator :
In this ceiling fan regulator circuit, R1=500KΩ is a variable resistor that is used to adjust the fan speed. Capacitor C1 2A104J is a Polyester film capacitor.
Pin Diagram of TRIAC(T1)- Z0607:
Pin Diagram of Variable Resistor R1:
Parts List Ceiling Fan Motor Speed Controller circuit:
T1 = Z0607 -TRIACD1 = DB3 C312 -DIAC
R1 = 500KΩ -Variable Resistor
R2 = 37KΩ -Resistor
C1 = 2A104J -Polyester film capacitor.
M1 = Single Phase AC Motor (Ceiling Fan)-220V,50Hz
Saturday, July 14, 2012
555 Timer Touch Activated Alarm Circuit Diagram
This is the circuit diagram of touch activated alarm system which still activated on load shedding. Alarm system will be activated when someone touch the “touch plate” which is called trigger. In this circuit the most updated part is automatic battery activator which is made by a relay. So don’t upset on load shedding you alarm system is activated. This circuit could be used at your home door, locker, vehicle or metal gate etc.
Monday, May 14, 2012
Automatic Emergency Light Circuit Diagram
This is the simple circuit of automatic emergency light. It is called dark dependent circuit. A 555 timer IC and LDR is used for this configuration. When light fall on the LDR, its resistance is decrease and in dark position its resistance is going high. Using these characteristics of LDR, automatic emergency light is made.
LDR is called Light Dependent Resistor. Its resistance is inversely proportional to the falling light on its surface. In dark, its resistance is approximately 7k to 10k. When light fall on its surface, its resistance is decrease to less than 1k. In the circuit, a voltage dividerarrangement circuit is used here with LDR and 10K variable resistor.
When light fall on the surface of LDR, the resistance decrease to 1k. So the voltage of the timer pin-6 is greater than 2/3 of +Vcc. For this reason the output pin-3 goes low. The base voltage of transistor BC547 is less than 0.75 volt. The transistor is OFF state. So the light is OFF.
In dark position the LDR resistance increase is high so the voltage of the trigger pin-2 decrease to less than 1/3 of +Vcc. The output pin-3 goes high so the base voltage of the transistor BC547 is greater than 0.75 volt. The transistor is ON state. So the light is ON and it emits light.
Wednesday, January 18, 2012
Dual Voltage Power Supply 12 Volt
This is the simple circuit diagram of Dual Voltage Power Supply. It is used for Misc… application. This circuit is called regulated power supply. For this reason the main component of this circuit is Regulator IC. It also needs few components to built. The regulator 7812 is the positive voltage regulator and 7912 is the negative voltage regulator.
It regulates voltage from 24Volt to 12 Volt (DC). The transformer input is 110Volt to 220Volt (AC) and the output must be between 12Volt to 24Volt (AC) and current must be 500mA. In this circuit some capacitors are used as a filter for removing repole.
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