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How to properly size a serial bulb for protection when troubleshooting a circuit?
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this post was submitted on 18 Jun 2023
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For this application you should be using a bench power supply with current limiting, not a "serial bulb" (I assume you mean a fuse, which is designed to break at a low current, however these are most typically rated for several amps, not typically in the mA range). You can set the voltage and a current limit. If the current goes beyond the limit, then the power supply will drop the voltage to keep the current below the limit or latch off. You can get a fairly cheap one for about $50-60 off of eBay, which won't be the best but is sufficient for hobby use
Hey, thanks for your reply. By serial bulb I mean a incandescent lamp in series with the circuit. I was looking for a cheap and diy option, but I'll take a look on a bench power supply. I still need to get me a decent one anyways.
Ah. It's not going to be possible to size it because the bulb is then acting as a resistor essentially. Unless you know what the equivalent resistance of the circuit you're testing is, and it draws a fixed current, you aren't going to be able to cap the current; Adding a resistor (or bulb) is just going to drop the input voltage and you will probably end up having other issues
Ah got it. Then a bench power supply is the way to go. Thanks again!