Monostable multivibrator using 555 timer

These are many Monostable multivibrators using 555 timers. We use them as timer circuits to control a load. For example, LEDs, or driver relay. Which trigger them by a normal switch. Please look at more below. I hope you are happy!

Monostable multivibrator using 555 timer

Here is the circuits diagram you can make that.

  1. Simple 555 timer with LED display
  2. Basic Timer Control circuit using NE555
  3. 555 IC Timer control relay Switch
  4. Egg timer circuits using IC-555

The 555 is good at making the timer. We often call it, 555 timers. It may be unique features of 555.

It is very easy to use. Just add a resistor and capacitor each one.

We so get a simple timer that can set the time as you want.

In the circuit below, take the 555 in the monostable multivibrator or the time delay circuit. It has the operation status of 2 levels. First, low voltage (logic “0”). Second, high voltage (logic “1”).

1. Simple 555 timer with LED display

Simple scheduling tool

In the circuit above. When press the switch S1. Pin 2 of IC-555 will be shorted to the ground. It is the trigger for IC-555 to active with the low voltage or logic “0”.

Then, the output pin 3 of IC gives the high voltage. It is the same as the power supply voltage. So, it makes LED1 glow up to show the time working.

This time can be set by changing the value of R2, C1, and VR1.

Below is a simple math equation.

For those who want to calculate the right time.

Time = 1.1 R2 x VR1 x C1

Also, You can set this time easily by adjusting the VR1.

2. Basic Timer Control circuit using NE555

Basic Timer Control circuit using NE555

As circuit below, we use LED display to show the timer circuit. But if we need to use others load.

For example, lamps, motors, and more.

In principle, the maximum current output of LM555 is about 200mA.

It has many ways to drive a high current load.

First, using transistors, easy and cheap. But it cannot use with AC load. Using the relay is the best way we like at all time. IC555 can drive the relay directly without helping of a transistor.

So easy and useful.

In the circuit above, to begin with,

Press the pushbutton switch-S1 just a brief moment. To start the Timing Cycle.

The relay will be pulled in. The current flow to the load. Until finishing the timing delay. The relay does not work.

R1 and C1 control the delay time. If more capacitance of C1, more time.

It is same as the above circuit. This circuit also responds to a logic pulse. Have fun with this simple timer circuit.

3. 555 IC Timer Control Relay Switch

555 IC Timer control relay Switch

This circuit is similar to the second. It is another idea of 555 timers with a relay switch.

4. Egg timer circuits using 555

Egg timer circuits by IC-555

This mini timer circuit is interesting. Some called the Egg Timer circuit. Also, I use The famous 555 IC, LM555 or NE555 or equivalent. Using VR1 to adjust the timing of the egg timer.

The S1 is a selector switch.

First, set S1 to “standby”. Pin 2 of IC open up. IC does not work. The buzzer will be silent. While the current flows R1 to charges in C1.

Second, set S1 to “time”. In briefly, C1 discharged, Pin 2 closed to turns IC-555 on.

The buzzer will be silent until the delay is complete. Then, the buzzer will emit alert us immediately.
Increase C2 or VR1, R2 for longer delays.

5. Timer control 1-15 minutes using Triac 2N6075 and LM555-LM358

In most timer circuits. Often we use a transformer to reduce a low voltage down of 9V and 12V. And the relay to control the load.

See in circuit below, the 1-15 minute timer circuit.

It uses a TRIAC  instead of electrical control, relay. This can be used with a 220V powerhouse. It is not connected to the transformer.

It causes this circuit is smaller and easy to use.

Timer control 1-15 minutes by Triac 2N6075 and LM555-LM358

We will divide this circuit into 3 parts.

  • Run with high-voltage level
  • Use Timer and
  • Control the electrical appliance.

When we enter 220V AC main to the circuit. There is a DC power supply R1, C1, D1, and ZD1. They run with a high-voltage level to reduce and keep the voltage to 10VDC.

This 10V input voltage is a power supply to IC1 No-555. Which it is a timer section. We set time by R3 and C3 at a specified time period as you want.

So, when a switch S1 (Start), IC1 work out as a pulse signal generator via the output pin 3 of IC1.

The VR1 is timer setting from 1-15 minutes. Then sent into the period to pin 2 of IC2 – LM358. Which it controls electrical appliances.

The output of IC2 a pin 1 has a higher voltage level of about 5V.
To stimulate the gate (G) of a TRIAC – T1.

Which a TRIAC acts as a switch on and off electrical appliances. When there is a voltage to G of TRIAC. It will conduct between MT1 and MT2 leads.

It result in appliances are working such as fluorescent light up.
And after that, time-out quits and IC2 to stop the flow with the TRIAC.

Also, we can stop the circuit. Or, IC2 stopped working, just press the switch S2 to reset or unplug the circuit.

Related Posts


I always try to make Electronics Learning Easy.

Apichet Garaipoom

I love the electronic circuits. I will collect a lot of circuit electronics to teach my son and are useful for everyone.
Notify of

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Inline Feedbacks
View all comments
Close Menu