I can't imagine any tester that can "reliably" test in-circuit. A simple DVM might test bipolar or FET junctions for obvious shorts/opens, but that possibility is governed by the surrounding circuitry.
Whenever possible, I advocate symptom-driven trouble-shooting with power applied, but that generally means you have schematics in hand. Experience helps but you learn/acquire that.
Good luck!
Whenever possible, I advocate symptom-driven trouble-shooting with power applied, but that generally means you have schematics in hand. Experience helps but you learn/acquire that.
Good luck!
They have been around for decades and they do work if the associated circuit is no too extreme. I have a B&K 530 http://bee.mif.pg.gda.pl/ciasteczkowypotwor/B&K/B&K 530 Semiconductor Tester.pdf that can test transistors in circuit, identify them etc. Out of circuit it can even check the Ft of the transistors.
I had a VuData that was similar. it was more industrial but also could test transistors for function in circuit. Vu-data 5110 transistor tester, calibrated, warranty
I think the Peak can also work in circuit. Peak Atlas DCA model DCA55 | Peak Electronic Design Limited
I had a VuData that was similar. it was more industrial but also could test transistors for function in circuit. Vu-data 5110 transistor tester, calibrated, warranty
I think the Peak can also work in circuit. Peak Atlas DCA model DCA55 | Peak Electronic Design Limited
I used one of those along time ago (in the 1970s) & it worked much better than I expected it to.
B&K Precision 530 Semiconductor / transistor tester | eBay
I still prefer an old Tektronix curve tracer, for testing the devices out of circuit, but since I retired, I no longer have access to one or the space to put one.
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Those in circuit testers look expensive. Its possible to test some things in circuit if the power is on and you know how the circuit works. If a BJT is on its Vbe will be around .5-.6v. Vce will not be a short (but it might be as low as .2v). If theres a resistor attached to the emitter or collector you can see if theres a collector current. If theres a base resistor you can check the base current and with these 2 currents get the transistor beta.(unless its saturated (Vce is .2v)). For fets things are different but still doable. More device dependent.
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The picture bought back memories a useful tester.
Loved the TEK curve tracer, model 37x series, easy to observe power transistor breaking down by voltage or current. Used to cutoff the TO3 case to see & learn from the damage at the junction.