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Home » Simple 220V Time Delay Switch Circuit with Triac

Simple 220V Time Delay Switch Circuit with Triac

Last updated on 27 May 2026 by Admin-Lavi Leave a Comment

Think this circuit is like a smart switch for our home things which wait for some time before power comes.

This Simple 220V Time Delay Switch Circuit with Triac work like power button but it does not gives power fast, but it waits for little time and then gives power to light, fan or motor.

We can choose how long it can wait for some seconds or maybe for some minutes.

Inside, it uses special part named as triac which is for controlling power.

We can use this for heater so there is not much load for the same time or for stage light which makes small wait before light is ON which looks nice.

Circuit Working:

Simple 220V Time Delay Switch Circuit Diagram with Triac

Parts List:

ComponentsValuesQuantity
Resistors22k 1/4 watt1
1k 1/4 watt1
220Ω 1/4 watt1
CapacitorsElectrolytic 1000µF 50V1
Electrolytic 470µF 50V1
Electrolytic 100µF 50V1
SemiconductorsSCR BT1691
Triac BT1361
Diode 1N40071

This circuit is for time delay switch which turns ON AC load like lamp after 3 minute delay, also it help protect load from big current rush and power spikes that can hurt the device.

Switch connect direct to AC power to work.

Resistor R1 drop the AC voltage and diode D1 change it to low DC voltage, also big capacitor C1 do two things it smooth the DC and also makes the delay time.

The SCR start work only after C1 is fully charge which takes near 2 minutes and when C1 is full SCR get small signal at gate and it start to conduct.

Then C2 start charging this gives 1 more minute delay to make Triac turn ON using R3.

When Triac turns ON AC power connects to load and device start working and capacitor C3 keep voltage stable at Triac gate and stops any flicker or problem.

Be very careful, as this circuit use high voltage from mains which can kill; so do not touch anything when power is ON, only expert person should build this circuit.

Formula:

RC timing circuit uses resistor and capacitor to make time delay for SCR circuit.

The resistor R and capacitor C decide how long delay happen, as this is simple formula to find time delay in RC circuit:

t = R × C × 1.1

where:

  • t is delay time in seconds R is resistor value in ohms Ω
  • C is capacitor value in farads F

Important things:

The 1.1 in formula help give correct timing, it fixes delay and SCR trigger time.

Choose resistor and capacitor with right voltage and power rating for the circuit.

Sometimes real parts are not the same as number written on them so test circuit to check real delay and with this formula we can make time delay using SCR, resistor and capacitor.

Also, if the circuit need different delay we can change R or C values to adjust it.

How to Build:

Below are the steps for building a Simple 220V Time Delay Switch Circuit with Triac:

Safety First:

  • First, make sure we work in a safe place and unplug all parts before we begin.

Circuit Design:

  • Look at the circuit diagram before we start.

Put Components:

  • Next, put all parts on breadboard or PCB same like in diagram and then leave space between parts so no short circuit happen.

Power Connection:

  • Now connect 220V AC power to circuit and be careful and use proper wire and cover for safety.

Test Circuit:

  • After building test the circuit by giving power.
  • Triac should turn ON after some time delay.
  • Time delay depends on R1, R2 and C1 and change these if delay is not right.

Connect Load:

  • If circuit works good then connect AC load like lamp to Triac output.

Final Check:

  • Check all wires again and be sure everything is tight and covered.

How It Works:

  • Turn ON the power and see how long it takes to turn ON the load and if delay is not perfect then adjust parts again.

Important Safety Warning:

  • This circuit uses 220V AC and is very dangerous! always be very careful and follow safety rules.
  • Cover all parts properly and connect them securely; also, if we do not know how to work with high voltage, ask someone with experience or consult a qualified electrician.

Conclusion:

To conclude, we can make Simple 220V Time Delay Switch Circuit with Triac using normal electronic parts, as this circuit waits for some time before turning ON AC load like lamp after power come.

Hence, be very careful when making and testing this circuit because it uses high voltage.

Filed Under: Automation Circuits, High Voltage, Mini Projects, Timer Circuits

About Admin-Lavi

Lavi is a B.Tech electronics engineer with a passion for designing new electronic circuits. Do you have questions regarding the circuit diagrams presented on this blog? Feel free to comment and solve your queries with quick replies

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