| Products > Test Equipment |
| Continuity Tester |
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| hugo:
--- Quote ---I did a google search and didn't see anything ... --- End quote --- You'll find a simple, inexpensive and well enginnered diy continuity tester, called "In-Circuit Conduction Tester" at http://elm-chan.org/works/cch/report_e.html Vtest: 500mV Itest: 100μA |
| rhb:
I suggest you consider the likely outcome of using a 7 V (33401A) or 9 V continuity tester on a 3.3 V MCU board. And if you forward bias a transistor junction ( .3 or .7 V) you'll run the risk of spurious results. Consider using a 0.5 V 1 kHz pulse train and an op amp to boost it to 5 V with a missing pulse detector triggering a 555 configured as a multivibrator. 0.2 V in the unlikely case you're working with germanium semis. There are many ways to implement one. I made a crude 1.5 V tester using a small, not loud enough, piezo sounder. It works OK, but I concluded it really needs to be below the forward conduction threshold for silicon junctions. The Cadillac is a milliohm RC oscillator which changes tone as the resistance varies. Those will let you locate shorts as well as opens. There are lots of versions of those. Have Fun! Reg |
| bdunham7:
--- Quote from: rhb on July 25, 2023, 02:04:01 am ---I suggest you consider the likely outcome of using a 7 V (33401A) or 9 V continuity tester on a 3.3 V MCU board. --- End quote --- Bench meters like the 34401A often have selectable continuity ranges and thresholds. You just set the threshold for a low value and then put a resistor just above that value across the test leads with one of those dual-banana adapters. So if your test current is 1mA just set the threshold for 10R, put a 20R resistor across it and your 'open circuit' voltage will be 20mV. |
| Fungus:
I always wanted one that has an LED in the probe. If you're going the DIY route you could try doing that. Edit: You could also pull the PCB out of one of those Anengs and build it around that - just bring the LED out to the probe. :) |
| J-R:
FYI, the 34401A continuity threshold can be set from 1-1000 Ohms. Default is 10 Ohms. |
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