The concept of negative resistance has always fascinated me. Of course, a true negative resistance is not possible, and what is meant is a negative differential resistance (NDR). But of course knowing ...

The digital voltmeter is the best basic tool for electrical troubleshooting, because it's calibrated and exact. But remember, the digital voltmeter can't detect a high-resistance fault if the circuit ...

The simplest model of a battery comprises an ideal voltage source that connects in series with a resistance whose value—often a few milliohms—depends on the battery’s electrochemical condition and ...

The “trimpot” is the standard solution to the analog designer’s occasional need to fine-tune a resistance in a precision circuit. But this old standby isn’t always available. For example, in some ...

Electrical snafus are among the most annoying problems with older cars. Unlike tires or bodywork, there's something about electrical systems that seems to baffle many car crafters. We could blame it ...

This simple but clever continuity tester sports two LEDs: RED LED = circuit resistance is < approx 10K, GREEN LED = circuit resistance <10Ω. It consumes approx 8mA from a 9V battery. When not ...