Simple Mains Voltage monitor

Advertise in delabs

This Circuit helps in the monitoring of mains supply voltage. It does not use a isolation step down transformer. This has to be constructed only by skilled people with knowledge of safety requirements.

C1 0.47uF can be brought down to 0.22uF for low LED currents, use high efficiency ultra bright LEDs.C1 should be 440V AC or 630V DC plastic axial yellow, polyester, polycarbonate, polypropylene, metalized film.

R3-R6-R9-R14-R18 resistor divider determines the LED turn on or threshold switch points, 10M for hysteresis.

Mains Voltage and Power Circuits

Adjust R16 preset with a log Plastic tweaker to get the led D2 to turn on when input voltage is at 220V AC. This has to be done after PCB is put in a sealed fire-retardant-plastic or epoxy box. drill a hole in box for plastic tweaker.

LM324 – Low Power Quad Operational Amplifier

This Circuit is Not a Tested Design. It is an Idea for study

Simple Mains Voltage monitor LM324

Warning : This Circuit is Mains Operated without Isolation Transformer and will give lethal electric shock if touched when the circuit is turned on. Test circuit only with DC 9V Bench Power Supply to try it out. Do not use 230V AC.

More delabs Schematic Diagrams

  • Simple Water operated relaySimple Water operated relay
    This was done in my early days, i have upgraded it, it ought to work, reduce the number of transistors to make it less sensitive, [...]
  • Current Source for Resistance MeasurementCurrent Source for Resistance Measurement
    Here is a current source you can build for resistance measurement. When the current is held constant, you know as per Ohm’s Law the Voltage [...]
  • Constant Current Source for LEDConstant Current Source for LED
    This article will explain the way a simple transistor based current source is designed, this will give an idea on how some components can be [...]
  • Passive volume control with PotentiometerPassive volume control with Potentiometer
    Volume control circuit for speaker 4 ohm or 8 ohm located in the another room far away. by using only passive components. This gives limited control [...]
  • InfraRed LED Flasher for Optical SwitchInfraRed LED Flasher for Optical Switch
    This circuit is used to detect objects by reflected infrared light. It can be built into a cylindrical enclosure just like an inductive proximity switch. [...]
  • Solid-State Stabilizer Step up 110V ACSolid-State Stabilizer Step up 110V AC
    The circuit uses opto-coupler MOC3041 of Motorola and the Triac BTA16-600 of STMicro as a solid state switch or relay. Four Switches boost or buck [...]
  • Fixed frequency Variable duty cycle with 555Fixed frequency Variable duty cycle with 555
    This circuit is based on a very old application note from exar, in this the frequency is fixed by IC1 and IC2 -P1 controls the [...]
  • Simple Printer Port InterfaceSimple Printer Port Interface
    Printer Port Circuit to see the inputs logic state and drive a few outputs. The preset control program helps test out the circuit operation. Use [...]
About delabs 152 Articles
Product Design - Industrial Automation and Instrumentation. -

Be the first to comment

Leave a Reply