Parts List


9 Volt Alkaline Battery and matching Battery Clip

LED Almost any type of LED will work

Resistor 330 Ohm or watt (Orange, Orange, Brown, Gold)

Clip Leads Buy a package of 10 (you will use them later)


The resistor and LED can be taped to the battery with electrical tape. For clips get a package of clip leads, the cheap ones about 10 for $3 and use the clips.


Test The Following


The Talk Circuit of the Telephone:

Connect this tester to one of the following: (a) The red and green wires of the telephone line cord, (b) Terminals in the phone where you think the line cord should be connected, or, (c)  If you have mod cord on the phone, get a jack and put it on the end of the mod cord, and connect this tester to the the red and green wires. If the phone is working you should hear yourself talk.


The Dial of the Telephone:

If you have a rotary dial telephone, dial a number, the LED should blink once per digit. If you dial a 4, the LED will go out and come back on 4 times. If you have a tone dial, you should hear a tone in your ear on the handset.


In general, you can test any electrical device, so long as there is NO POWER present, this means it cannot be plugged into the wall or have any batteries in it. Example: Unplug your toaster from the wall, connect the clips to the plug, the LED should not be on. Push down the handle of the toaster, just like you were going to toast a piece of bread. The LED should go on.


Have Fun!