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Another use for Bob's ESR meter

Discussion in 'Hobby Electronics' started by Phil Allison, Aug 29, 2011.

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  1. Phil Allison

    Phil Allison Guest

    ** 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
     
  2. Tom

    Tom Guest

    How much DC voltage can you apply to Bob's meter?
     
  3. 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.
     
  4. Phil Allison

    Phil Allison Guest

    "Tom"
    ** 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
     
  5. David

    David Guest

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

    David
     
  6. Do you still have it?
    How much?

    Joseph
     
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