When you need a multimeter for testing electrical equipment around the home, it's vital to know what all those symbols around ...

To take a 2-wire resistance measurement with a benchtop multimeter, select the “ohm” or “Ω” mode, and connect the probes to the “INPUT HI” and “INPUT LO” ports. Ensure the circuit ...

You also need a sinusoidal signal because the sound card’s inputs are AC-coupled. The sound card’s audio output can produce an AC voltage at the microphone input, whose amplitude is proportional to R/ ...

This multimeter add-on is called the Half Ohm. It allows you to measure small resistance values, and can be used to track down shorts on a PCB. The board acts as a pass-through for both probes. Whe… ...

When I ran an electrical test lab a few years ago, I had an old analog HP 4329A high resistance meter with its own test cell from the 60’s or 70’s.

Write down the ‘normally closed’ resistance reading obtained and compare it to the resistance specified in the PIR instruction sheet (e.g. 10.0 Ohms). Providing the reading is to within plus or minus ...

Figure 1 shows the easiest way tointerface a thermistor to a sound card.The microphone input has an internalbias resistor, R, with a typical valueof 2 to 5 kΩ. A dc bias voltage drivesthis resistor.