Continuity Tester
;)
A continuity tester is a pretty simple beast.
Take an LED and connect it to a battery with a big enough resistor to keep it from frying.
Congratulations, you've made a light.
Next, snip a wire between the LED and the battery. Attach some wires.
Now, you've got a light that only lights up when the wires touch or are connected by something with really low resistance.
That's a continuity tester.
So why do you care? Say you're making a thingie to connect an SNES gamepad to your PC... It's handy to be able to tell what wire at one end of a cable is connected to what plug on the other end.
Stuff we'll need:
- An LED
- A battery connector and a battery
- A resistor (use an LED calculator to figure out how big)
- A box to put it in
- some wire to use as probes
- (opt) some aligator clips or pointy nails to use as ends of the probes