Showing posts with label 555 timer. Show all posts
Showing posts with label 555 timer. Show all posts
Friday, November 2, 2012
Freeze Protector Circuit
This is the simple freeze protector circuit diagram. It is also called timing circuit. It is just hobby project for beginners. When you need to operate automatically any device in the fixed time later after coming AC power supply, you can use this circuit.
The voltage amplitude
is high when AC power come. Suddenly high voltage destroys the
electronics device. For this reason, in the time of load shedding we
need to switched off electronics device (Audio/Video player, CD/DVD
Player, TV, Freeze or any electronics device). This circuit solve this problem.
Hobby Electronics helps the beginners to know the timing circuit specially using 555 IC
timer. NE555 IC is the very simple well known parts. Its configuration
is very simple. You can use this timer any simple circuit.
In this circuit use 12volt
power supplies. 300k variable resistor is used for timing control.
Timing resistor and capacitor are 300k and 1000uF. Only change the value
of the variable resistor for your required timing.
The circuit output pin 3 is connected with resistor (10k) and output 12 volt relay. Relay is connected as figured with the device. Making cost is too low. Anyone can make this circuit easily.
4017 LED Knight Rider Running Light Circuit Diagram
In this 4017 Knight Rider circuit, the 555 timer is
wired as an oscillator. It can be adjusted to give the desired speed
for the display. The output of the 555 is directly connected to the
input of a Johnson Counter (CD 4017).
Continue Reading here[...]
The
input of the counter is called the CLOCK line. The 10 outputs become
active, one at a time, on the rising edge of the waveform from the 555. Each output can deliver about 20mA but a LED should not be connected to the output without a current-limiting resistor (220Ω in the circuit above).
The
first 6 outputs of the chip are connected directly to the 6 LEDs and
these “move” across the display. The next 4 outputs move the effect in
the opposite direction and the cycle repeats. The animation above shows
how the effect appears on the display. Using six LEDs,
the display can be placed in the front of a model car to give a very
realistic effect. The outputs can be taken to driver transistors to
produce a larger version of the display.
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.
Friday, February 25, 2011
Frequency Meter Circuit
This is the circuit of frequency meter. It measures the frequency of the input signal in terms of current passing through an ordinary ammeter. The main component of this circuit is the 555, a versatile, general-purpose timer IC. In this circuit, the 555 is configured as a monostable multivibrator that outputs a single pulse at pin 3 every time the input signal at pin 2 goes 'low'.
The width of the output pulse generated by the 555 is defined by R3 and C3. The larger the output pulse width, the longer is the time that pin 3 is high. Since pin 3 doesn't sink current when it is high, the current passing through the ammeter is higher when pin 3 is high.
This means that the larger the values of R3 and C3 are, the larger is the output pulse width, and the higher is the current passing through the ammeter for a given input frequency.For any given value of R3 and C3, on the other hand, the current passing through the ammeter increases as the input frequency increases.
This is because pin 2 is 'retriggered' more often as the input frequency increases, decreasing the total duration wherein the output is 'low'. Thus, the ammeter dial in this circuit would be a good indicator of the relative frequency of the input signal at pin 2. Good choices for the values of R3 and C3 to match the intended application as well as careful calibration through R5 are required to make this simple circuit work properly.
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