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-   -   Easy way to measure battery supply current. (https://www.vintage-radio.net/forum/showthread.php?t=137951)

Biggles 5th Jul 2017 5:22 pm

Easy way to measure battery supply current.
 
I can't claim originality for this idea but if you need to measure how much current a set is taking from it's battery, solder wires to either side of a small piece of double sided PCB, and insert it between cells in the holder. Current can then be easily measured with an ammeter connected to the free wires, as the PCB breaks the circuit, enabling a series measurement to be made. It may be necessary to build up the connections with a blob of solder to ensure a good contact with the cells.
Alan.

David G4EBT 5th Jul 2017 6:12 pm

Re: Easy way to measure battery supply current.
 
Like this:

http://www.vintage-radio.net/forum/s...attery+current

Guest 5th Jul 2017 7:07 pm

Re: Easy way to measure battery supply current.
 
Yes, a good old trick well worth re publicising. You can use ali foil and paper for those thinner places like button cells.

Tim 7th Jul 2017 12:06 am

Re: Easy way to measure battery supply current.
 
If your set has an easily accessible on off switch, just connect your ammeter across it when in the off position.

Guest 7th Jul 2017 8:52 am

Re: Easy way to measure battery supply current.
 
Quote:

If your set has an easily accessible on off switch, just connect your ammeter across it when in the off position.
Tricky to measure the "high volume" current with a combined vol/on/off control!

Tim 13th Aug 2017 1:00 am

Re: Easy way to measure battery supply current.
 
"Tricky to measure the "high volume" current with a combined vol/on/off control"

Yes true, but it's a good trick to measure the normal current and to verify the set isn't taking too much, such as for a short battery life fault.
Something I have done in the past is to connect the ammeter to two small squares of kitchen foil, each stuck to opposite sides of a piece of card or thin plastic, a 5 minute make version of the old trick above.
You can slide that in between two of the batteries, which will then obviously connect your meter in. Of course with a PP9 or whatever, you can connect the meter in at the battery clip.

Phil G4SPZ 13th Aug 2017 10:15 pm

Re: Easy way to measure battery supply current.
 
Now that I have a decent variable-voltage power supply with variable current limit and twin meters, I tend to use that. However, in the field the current probe described is a great idea. I first saw it mentioned in 'Sprat' magazine back in the 1980s but it probably originated long before then!


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