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Old 15th Jan 2017, 11:28 pm   #1
dragonser
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Default Wayne Kerr B641 bridge quick instruction guide

Hi,
many years ago I bought a Wayne Kerr B641 universal bridge with operations manual.
Well of course I have managed to misplace the manual....
I just wondered if anyone knew how to use the bridge or a similar model, so that until I find where I have placed the manual I can try it out again ?
I am going to power it up carefully with a variac as it hasn't been used for many years.
I'm attaching a not very good picture as there doesn't seem to be much info on the web.
regards Peter B
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Old 16th Jan 2017, 1:09 am   #2
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Default Re: Wayne Kerr B641 bridge quick instruction guide

I have one.
I don't think I have a manual, though, but there might be a set of schematics, but I don't remember where I put them.

The bridge has two sections, measuring impedance at 90 degree phase shift. C measures capacitance while G measures conductance.

Switch on. select the appropriate impedance (note the negative switch for C allows you to measure inductance, but you have to do a bit of arithmetic. All the number buttons must be out (press the four red ones) the two black 'knobpots' should be fully anticlockwise. Connect the part to measure. Pick a range button, any rang button 1 to 7. Do you get both meters reading on-scale? and at least one of them showing somewhere between 1 and 10? If not change the range button pressed up or down until you get a goor reading.
Now read the C meter And press the integer part of that reading into the topmost bank of C number buttons EG for 7.6 showing on the meter, press '7'
Now read the G meter and press the appropriate integer on the top row of G number buttons.

The nixies come on showing the buttons pressed, and the meters have that integer subtracted from them and their sensitivity increased x10.

So now read the integer part on the C meter and press that button on the second row of C numbers.

Read the integer part on the G meter and press the appropriate button on the second row of G.

More nixies come on, the values are subtracted from the meters and the meter sensitivities go up again.

Read your results from the nixies, and read the meters to get the next digit and interpolate the next further digit. You can use the knobpots to wind the meters back to zero and read from the longer 10-turn scale on them.

There are all sorts of added tricks. The beastie will even run off a batery if you don't mind reading the buttons without the help of the nixies.

Note that this W-K bridge has its low impedance adaptor built in.

It really is a fabulous beast.

David
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Old 16th Jan 2017, 3:08 am   #3
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Default Re: Wayne Kerr B641 bridge quick instruction guide

Hi Peter,
You can find some B641 description here and they has it too...
Karl

Last edited by karesz*; 16th Jan 2017 at 3:17 am.
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Old 16th Jan 2017, 11:54 pm   #4
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Default Re: Wayne Kerr B641 bridge quick instruction guide

Hi,
thank you both for the very useful info above.
regards Peter B
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Old 20th Jan 2017, 9:11 pm   #5
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Default Re: Wayne Kerr B641 bridge quick instruction guide

Peter,
Ok, but between comments you will/can find some names/links who has your doc
Regards, Karl
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