Hello,
I was testing a 2N3904 transistor at my work with a newer Radio Shack analog multimeter, how I usually do, by measuring resistance between base and collector, and base and emitter. It seemed to measure the exact opposite, meaning no current would flow when forward biased, but current passed reversed. So I thought the transistor might be bad.
So I brought a new 3904 from home, and tested it with my Simpson 260. It measured as I would expect. The + lead on the base passes some current when the - lead is on the emitter or collector, and passes no current when reversed. I also brought a 1N4148 diode that measured the same way with the Simpson.
But at work, the Radio Shack meter measures both of those exact components opposite. There is no polarity switch. We also have an even cheaper, hardware store analog multimeter, and I tested the transistor and diode with the exact results as the Radio Shack.
All three meters are set to Ohm. The Simpson and the Radio Shack were set to R x 1, the third meter is set to its lowest, R X1k
Can anyone explain why I’m getting opposite readings on these meters?
Thanks!
I was testing a 2N3904 transistor at my work with a newer Radio Shack analog multimeter, how I usually do, by measuring resistance between base and collector, and base and emitter. It seemed to measure the exact opposite, meaning no current would flow when forward biased, but current passed reversed. So I thought the transistor might be bad.
So I brought a new 3904 from home, and tested it with my Simpson 260. It measured as I would expect. The + lead on the base passes some current when the - lead is on the emitter or collector, and passes no current when reversed. I also brought a 1N4148 diode that measured the same way with the Simpson.
But at work, the Radio Shack meter measures both of those exact components opposite. There is no polarity switch. We also have an even cheaper, hardware store analog multimeter, and I tested the transistor and diode with the exact results as the Radio Shack.
All three meters are set to Ohm. The Simpson and the Radio Shack were set to R x 1, the third meter is set to its lowest, R X1k
Can anyone explain why I’m getting opposite readings on these meters?
Thanks!