Another use for Bob's ESR meter

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** Hi all,

one of the most useful gadgets a service tech can own is Bob Parker's famous
ESR meter. Not only will it check the ESR of nearly any electro  * IN
CIRCUIT *  -  it also reads resistors from about  0.1 ohms up to 99 ohms.

It will not generally matter if the particular resistor has an inductor ( ie
in a speaker crossover network ) or transformer winding in parallel  -  as
the test signal is a 100 kHz pulse wave.

Bob's meter will also check the ESR of cells and batteries, from the tiniest
lithium button cells up to NiCd and NiMH packs. Along with a simple voltage
test, it tells you a lot about the condition and state of charge of such
cells.

One more use is when servicing SMPS  -  often a  MOSFET or high speed diode
will have a switching transformer winding in parallel making it test *dead
short* with an ohm meter.

Instead cutting leads to isolate the part so you can test it, just use Bob's
meter.

You will soon see if it really is shorted or not.


...  Phil






Re: Another use for Bob's ESR meter
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How much DC voltage can you apply to Bob's meter?

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Re: Another use for Bob's ESR meter

"Tom"
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** See schem of Mk 2 version:

http://electronichobby.info/wp-content/uploads/2011/05/digital-esr-meter-mk2-circuit-board.jpg

In theory -  up to 50 volts DC, providing C6 is rated for that.

In practice  - any DC voltage you like IF you use an electro cap of about
100uF to isolate DC to the meter.

Step 1.

Zero the ESR meter with the electro in series.

Step 2.

Charge the electro across the DC voltage source.

Step 3.

Connect the electro and ESR meter across the DC source in series.

NB

Don't let the voltage source or the electro BITE you !!



....  Phil





 



Re: Another use for Bob's ESR meter
Phil,

That's excellent - thanks so much for reporting.

I've had one of these kits unbuilt on the shelf
for over a year now - musty put it together!

Clifford Heath.

Re: Another use for Bob's ESR meter

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...and I have an unbuilt kit I want to sell - any interest here?  any
offers?

David

Re: Another use for Bob's ESR meter
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Do you still have it?
How much?

Joseph

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