Comments on: Testing PWM UC3842 With Analogue Meter

By: alan

alan — Tue, 27 Feb 2018 11:32:47 +0000

Can someone reupload the test circuit please

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By: admin

admin — Sat, 07 Aug 2010 20:47:14 +0000

Hi Rajender,
You can only test the pwm ic using voltmeter and scope. Find the spec of the ic and look for the vcc oin from there power on the set and measure the vcc pin of the ic to see if the supply is good or not and if it is good you can then use scope to check the output of the ic with scope.

Jestine

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By: RAJENDER SHAH

RAJENDER SHAH — Fri, 06 Aug 2010 17:17:37 +0000

sir,
plz. tell me how to test pwm ic with multimeter?

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By: admin

admin — Wed, 05 Aug 2009 12:08:20 +0000

Hi Jon,

Thanks for sharing and yes many times the e-cap cause lots of problem like low output voltage, no power and shutdown too.

Jestine

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By: Jon Pippard

Jon Pippard — Tue, 04 Aug 2009 01:26:57 +0000

Very often the IC is OK, but the startup or bootstrap electrolytic has dryed out. Before changing the IC change the bootstrap capacitor, usually 10 -47uF 25V.

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By: admin

admin — Thu, 23 Oct 2008 14:03:29 +0000

Hi Libero,

Thanks for sharing the circuit. It will be very helpful!

Jestine

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By: Líbero

Líbero — Thu, 23 Oct 2008 12:03:35 +0000

The complete link is: http://www.sosmonitores.com.br/dicas/testpwm.html

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By: admin

admin — Mon, 21 Jul 2008 08:00:37 +0000

Thanks for sharing but the link is not working. Anyway thanks again for the good tip.

Jestine

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By: Truckman Jones

Truckman Jones — Fri, 18 Jul 2008 13:15:56 +0000

I found this method of testing this pwm, practice shows that this method works ok, but I cannot guarantee also I'm not the author of the desing...
http://www.sosmonitores.com.br/imagens/pwm/Pwm.jpg
If LED is flashing ic is good, the pot regulates the frequency. Otherwise IC is bad.
Hope that it'll help anyone...

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