Introduction: Momentary to Latching Switch Conversion With This Simple Circuit

By Ben Bogard Personal Site
About: I'm 16 years old and live in Bradenton, Florida. I like Ham Radio, very fast SBC's, and giant capacitors! Also a bunch of other stuff that I can't think of right now :)

Have you ever wondered if you could use a wee little momentary tact switch to turn large high voltage high current things on and off? Wonder no more!! Use this instructable and the circuit schematic to build yourself a latching circuit!

Step 1: Watch the Video

First things first, watch the video and see how I built the circuit. The video is all encompassing, but further on in this instructable you will find some more detailed instructions and some tutorial videos.

Step 2: Gather Supplies

For this circuit you will need:

1 N-Channel FET

1 PNP Transistor

1 330nF Electrolytic Capacitor

1 Silicon Diode

3 10k Resistors

1 100k Resistor

1 1M Resistor

1 Push Switch

Step 3: Learn to Breadboard (optional)

If you don't know how to use a breadboard, watch this video tutorial.

Step 4: Prototype the Circuit on the Breadboard and Test

Start by using the schematic above to prototype the circuit on a breadboard and test it. If it doesn't work, check your connections!

Step 5: Transfer the Circuit to Perfboard

Once you have built and tested the circuit on a breadboard, proceed to transfer the circuit to a perfboard. Perfboards are basically a bunch of holes with circular copper pads on each hole. Transfer the circuit, following your breadboard and the schematic. Don't forget to solder everything up!

Step 6: Done!

Congratulations, you're done! You can use this new circuit in conjunction with a relay to control high voltage high current loads using a very small switch! Each time you push the switch, the circuit changes state. Push once to turn everything on and hold it there and again to turn it all off.

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