How do I test the CA3026 dual transistor?

Discussion in 'General Electronics Chat' started by ronsuzuki, Feb 9, 2012.

  1. ronsuzuki

    Thread Starter New Member

    Feb 9, 2012
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    I have a transistor tester, I've tried testing it, but the tester says the transistor works in the wrong pinouts. I've tested other transistors, and it everything was fine. Anybody out there have any experience testing dual matched transistors? The tester is a BK precision 520.
     
  2. BSomer

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    Dec 28, 2011
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    What exactly do you mean by "works in the wrong piouts"? Is your tester telling you the emitter is the collector and such? I have generally used a digital multimeter to test transistors. Place the DMM in diode test mode and probe the transistor.

    For instance if you have a NPN transistor:
    red to base and black to collector - good gives volt reading
    red to base and black to emitter - good give volt reading
    red to emitter and black to collector - good gives volt reading.
    any other configuration should be open.

    This test should work for your dual transistors. Give it a try and see.
     
  3. Ron H

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    Apr 14, 2005
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    Emitter-collector should be open with either polarity of test leads, unless your meter has a high enough voltage in diode test mode to break down the base-emitter junction. This breakdown voltage is usually more than 5 volts, typically 6 to 8 volts. It is generally not a good idea to break down this junction, although doing it for a few seconds when limited to a few milliamps is generally not harmful.
     
  4. Ron H

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    You don't have access to all 3 terminals of ANY of the transistors in a CA3026, so how can you test them on a transistor tester?
    I could test them, but it would require a custom circuit. I don't believe it can be done on your 520.
     
  5. BSomer

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    Dec 28, 2011
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    oops.. right... My fingers were working faster that my brain yesterday. :rolleyes:
     
  6. ronsuzuki

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    Feb 9, 2012
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    How would you test them?
     
  7. ronsuzuki

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    Feb 9, 2012
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    I'll give that a try. thanks!
     
  8. Ron H

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    I reiterate - You don't have access to all three terminals of any of the transistors.
     
  9. Ron H

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    I'm not sure, without giving it more thought. Also, it depends on what parameters you want to test.
     
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  10. ronsuzuki

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    Feb 9, 2012
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    Just a pass/fail test?
     
  11. Ron H

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    What test equipment do you have (multimeters, power supplies, oscilloscope)?
     
  12. ronsuzuki

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    Feb 9, 2012
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    my testing equipment is the NK precision transistor tester, two DMM's, one with continuity tester. Hewlet packard test oscillator and a hewlet packard oscilloscope. Also reisistor decade boxe, variable power supplies, capacitor decade box. Everything works fine. Unfortunetly I just sold my cacitor tester.
     
  13. Ron H

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    This has a lot of resistors, but it tests each transistor as a switch. If it will work as a switch, it should work in analog applications.
    With the switch in the ON position, c1 and c2 should be complementary square waves, swinging from ≈0.3V to ≈4.8V. C4 and c5 should also be complementary square waves, swinging from ≈0.3V to 5V.
    With the switch in the OFF position, all outputs should be at 5V. You will see some small glitches on them.
    There are other ways to test this part, but I can't think of any that are substantially simpler.
     
  14. ronsuzuki

    Thread Starter New Member

    Feb 9, 2012
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    thanks, sorry for the delay.
     
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