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Make an LED AC Voltage Indicator Circuit

Make an LED AC Voltage Indicator Circuit

A simple construction and accurate result are the main features of this tiny circuit. Learn how to make ac voltage indicator from led in a most simple and easy to understand method.

Why Monitor AC Mains Voltage Level

The AC mains line that we get in our household electric socket outlets, may at times be full of dangerous fluctuations. These may either be in the form of a sudden high voltage or a low voltage.
Both the situations can be very “fatal” to our sophisticated electronic equipments like TVs, DVD players, refrigerators, computers etc to name a few.

A simple electronic part such as an LED can play an important role in displaying the condition of this AC mains voltage and warn us of a possible electrical hazard. Yeah, we will exactly learn how to make ac voltage indicator using leds through a construction of a little electronic circuit.

mains AC voltage monitor circuit

How to Construct the LED AC Voltage Indicator

It is completed through the following few easy steps:

In the procured general purpose board, with the help of the circuit schematic start inserting the transistors first in a straight line and solder their leads.

Similarly insert and solder the resistors, zener diodes, LEDs, capacitors, presets etc. in an organized manner and solder them with reference to the circuit diagram.

How to Test the Circuit?

The following testing details will furthermore help you to understand exactly how to make ac voltage indicator from led:

For testing the completed circuit board you will require a transformer with multiple voltage outputs. Connect the transformer to the AC mains; also connect the common secondary output of the transformer to the negative point of the circuit. Make an alligator clip/ wire assembly. Solder the wire end of the clip to 1N4007 diode input.

Now bite the clip to the 3 volt output of the transformer, adjust P1 so that the first LED just starts glowing. As above go on connecting the clip to 6, 7.5, 9 and 12 volts of the transformer and adjust the presets P2, P3, P4 andP5 so that the relevant LEDs just start to glow at the respective voltages. This completes the testing and the setting of the circuit.

Finally join the 6 volt transformer to the circuit and switch ON the power. You will find that LED 1, 2 and 3 are glowing brightly,

LED no.4 is glowing with less brightness while the last LED is completely OFF, indicating a safe level of AC mains voltage. Now in case the voltage exceeds a high level (above 260 volts) the last LED will start glowing brightly indicating a dangerous situation.

If the voltage drops to a dangerous level (below 160 V) LED 3 and may be LED 2 may cease to glow, again indicating a bad low voltage.

Parts Required

You will need the following mentioned parts for the project:
TRANSISTORS T1, 2, 3, 4, 5 = BC547
ZENER DIODE Z1----Z5 = 3 VOLTS / 400mW
CAPACITOR C1 = 1000uF/25v,
DIODE D1 = 1N4007
LED 1, 2, 3, 4, 5 = RED 5mm DIFFUSED
PRESET P1, 2, 3, 4, 5 = 47K LINEAR


About the Author

I am an electronic engineer (dipIETE ), hobbyist, inventor, schematic/PCB designer, manufacturer. I am also the founder of the website: https://www.homemade-circuits.com/, where I love sharing my innovative circuit ideas and tutorials. If you have any circuit related query, you may interact through comments, I'll be most happy to help!

4 thoughts on “Make an LED AC Voltage Indicator Circuit”

  1. thanks a lot.
    I understand that.but what I mean is, to make the AC line automatically switching off from the appliance as soon as it detected the unsafe zone.

  2. Good after noone Sir!
    Is it not good idia to develope this circuit in order to use more of it?I mean,as soon as voltage exceeds 260v and drops blew 160v,the AC line go to the "off" position.Is that not helpfull for the needy people who can not afford to buy voltage stabilizer?
    God bless you more and more for your nice work!

    • thanks, below 160V and over 260V are unsafe zones so as soon as this is detected, the user can simply switch OFF the mains….so the above circuit definitely can be useful if used sensibly

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