Categories :

What is the pin diagram of 555 timer?

What is the pin diagram of 555 timer?

The 555 timer IC consist of 8-pins where each pin has some function. The pin configuration of this IC is shown below. Pin-1 is a GND pin which is used to supply a zero voltage to the IC. Pin-2 is a trigger pin which is used to convert the FF from set to RST (reset).

What does pin 5 do on a 555 timer?

Pin 5. – Control Voltage, This pin controls the timing of the 555 by overriding the 2/3Vcc level of the voltage divider network. By applying a voltage to this pin the width of the output signal can be varied independently of the RC timing network.

How many pins does an lm555 time have?

The pinout of the 8-pin 555 timer and 14-pin 556 dual timer are shown in the following table.

How can you avoid false triggering of 555 timer the reset pin is generally connected to?

To eliminate the false triggering resistor R1 and Capacitor C1 are connected to the reset pin 4 of the IC. So the reset pin is always high even if the supply voltage changes. Moreover capacitor C3 connected close to the Vcc pin 8 acts as a buffer to maintain stable supply voltage to pin 8.

What are the features of 555 timer?


  • Direct replacement for SE556/NE556.
  • Timing from microseconds to hours.
  • Operates in both astable and monostable modes.
  • Replaces two 555 timers.
  • Adjustable duty cycle.
  • Output can source or sink 200mA.
  • Output and supply TTL compatible.
  • Temperature stability better than 0.005% per ˚C.

What is the function of the pin 7 in 555 timer?

Discharge: Pin 7 is called the discharge. This pin is used to discharge an external capacitor that works in conjunction with a resistor to control the timing interval.

How do you control a 555 timer?

For standard 555 timers use timing resistor values between 1K ohms and 1M ohms. Figure 6 shows a complete 555 monostable multivibrator circuit with simple edge triggering. Closing switch S1 starts the 5 second timing interval and turns on LED1. At the end of the timing interval LED1 will turn off.

How much voltage can a 555 timer take?

Pin 8 (V +): The V+ pin (also referred to as Vcc) is the positive supply voltage terminal of the 555 timer IC. Supply-voltage operating range for the 555 is +4.5 volts (minimum) to +16 volts (maximum), and it is specified for operation between +5 volts and + 15 volts.

What is the function of pin 3 in 555 timer?

555 Signals and Pinout (8 pin DIP) Pin 1 – Ground (GND) This pin is connected to circuit ground. A low voltage (less than 1/3 the supply voltage) applied momentarily to the Trigger input causes the output (pin 3) to go high. The output will remain high until a high voltage is applied to the Threshold input (pin 6).

Why is it called 555 timer?

The 555 Timer IC got its name from the three 5KΩ resistors that are used in its voltage divider network. This IC is useful for generating accurate time delays and oscillations.

Why is it called IC 555 timer?

What is the function of pin No 2 in IC 555 timer?

Trigger: Pin 2 is the trigger, which works like a starter’s pistol to start the 555 timer running. The trigger is an active low trigger, which means that the timer starts when voltage on pin 2 drops to below one-third of the supply voltage. When the 555 is triggered via pin 2, the output on pin 3 goes high.

How to control duty cycle of a 555 timer?

Solving for t off gives a familiar relation for the 555 timer in astable mode. As we have seen, applying a voltage to pin 5 will change the duty cycle and period by changing the amount of time the output is high while the amount of time the output is low is constant.

Where is the output pin on a 555 timer?

The output is either low, which is very close to 0V, or high, which is close to the supply voltage that’s placed on pin 8. The output pin is where you would connect the load that you want the 555 timer to power.

How is the threshold voltage on a 555 timer set?

You can control the threshold voltage (pin 6) through the control input (which is internally set to 2/3 the supply voltage). You can vary it from 45% to 90% of the supply voltage. This enables you to vary the length of the output pulse in monostable mode or the output frequency in astable mode.

How does pin 6 affect the duty cycle?

The voltage of pin 6 will “bounce” between 0.5 V ctrl and V ctrl. When the voltage of pin 6 is on the way up pin 3 is held high, and when the voltage on pin 6 is decreasing pin 3 is held low. The duty cycle and period of the pulses will depend on the resistances and capacitance you choose.