Self Medicating > General DIY

Dim Light Bulb Tester


Hi, if you don't have one of these but you build electronics then you should make one.

The purpose is to prevent total destruction of your new device. If you insert a bulb that is about the power the device should draw or a bit less, it will light up bright instead of your new device lighting up bright when you have a problem. If it stays dim you're in the clear for say an idling amp.

Example problem, poor insulation between a chip and heatsink causes huge current to flow through the chip to heatsink, back to ground. Chip cooks... But if you used a dim light bulb tester it wouldn't fry it right away, you'd see the light bulb go bright and turn it off.

Here's mine. The light bulb must be in series with the hot (black wire, small blade, nickle colored screws). I made mine with a switch, using a light bulb adapter, plastic box, couple of strain relief inserts for plastic, and a couple extension cord ends. All supplies can generally be found at Lowes/Ace etc.

Here's a device working safely.

Here's a schematic.

Mine has a switch where one of the sockets is at, instead of inline going to them.

Guy 13:
Hi Folsom and all.
Of course the light bulb must be of the incandescent type bulb (Filament)
not the CFL or LED.

Guy 13


Barry (NJ):


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