Introduction: DIY AC 3-Pin Socket Tester

About: Electrical, electronics, IoT, programming and wireless stuff is what I love the most.

AC 3-Pin Socket Testers are very simple electrical circuit testing tools. Just plug-in the tester and turn on the switch of the socket, the LEDs will detect any probable simple faults that the circuit might have.

Materials Required:-

  1. A 10 A 3-pin socket - 1 piece.
  2. 47K, 1 or 2 W (preferably 2 W) resistors - 3 pieces.
  3. 1N4007 diode - 3 pieces.
  4. 5mm LEDs ( Red, Green & Blue) - 1 piece each colour.
  5. Insulated connecting wires (if required).
  6. Soldering iron.
  7. Solder.
  8. PVC box (optional) [ You can also drill holes into the socket and make everything inside it]

Step 1: Faults to Be Detected



ON OFF OFF Missing Earth

OFF ON ON Live-Earth Reversed

ON OFF ON Live-Neutral Reversed

OFF ON OFF Missing Neutral

OFF OFF OFF Missing Live/ Missing Neutral & Earth

Step 2: Schematic

Due to the high heat generated, a 2W resistor is preferred. If the LED glows dim, change the resistor value to a lower value or vice versa.

Step 3: PCB Designing

My PCB is designed using .

Make changes according to your needs.

Step 4: Developing PCB

Develop PCBs at

The PCBs will be provided if you need (contact for buying), but you can develop yours too.

You can omit PCB by directly soldering inside the socket, or use a veroboard.

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