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Looking Back at Yesteryear's Measurement Tools

Alix Paultre
8/22/2017 00:01 AM EDT

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sixscrews
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Re: Battery tester
sixscrews   8/23/2017 6:51:38 PM
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Yah - my 'Devil's Fork' was the 2 V version - needed to have cell access points to use it.

Wish I had kept it but there is only so much stuff you can keep over 50+ years of messing with hardware - just ask my wife.

Worked great way back when - guess we both come from the 'bad old days.'

I built a 6/12 V tester using heating elements from several waffle irons bought from a thrift store and connected using welding cables. It included an induction ammeter and connections for my voltmeter - worked OK for short term tests as the elements got very hot on a healthy 12 V battery.

Didn't often use it on 'good' batteries. But it was a good way to convince people to buy a new battery from me.  

A bit more honest than squirting oil on shock absorbers.

ss/wb

David Ashton
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Battery tester
David Ashton   8/23/2017 4:45:29 AM
In the good old days (from whence I come) car batteries had the individual 2V cells externally connected to form a 6V or 12V battery.  SO you could get at the individual 2V cells with just such a tester as shown, and measure them individually. A friend of mine bought a 12V version recently off EBay - same thing - a hefty resistor with a voltmeter across it.  Has to be 12V these days because the interconnections are inside the battery.

sixscrews
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Battery Tester
sixscrews   8/22/2017 11:02:59 PM
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I used to use one of these battery testers on 6V/12V automotive batteries in the late '60s-early '70s.

Similar units are still used in auto repair shops worldwide.

Most don't have the same 'devil's fork' shape anymore as terminal configurations are varied but the principal is the same - drop a big load across a charged battery and see what output current it can sustain.

You can't say much about a lead/acid battery unless you can test it under high discharge conditions as the internal resistance is not measurable w/o dropping a big load across it.

ss/wb

 

sixscrews
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Re: The Wheatstone Bridge
sixscrews   8/22/2017 10:49:11 PM
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And may of them think they are supposed to make a Whitestone Bridge - good luck.

wb

squirrelwhispher
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The Wheatstone Bridge
squirrelwhispher   8/22/2017 6:23:06 PM
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In universities the honor society for Electrical Engineers is known as HKN (Greek which sounds like Ate A Cap A New). Part of their induction ceremony created many moons ago instructs them to emulate the Wheatstone Bridge and achieve balance in their life like this tool for measuring RCLs. It always amuses me because none of them has ever used or even seen a Wheatstone Bridge. They were all replaced with digital RCL meters. Someday everthing we use will be in a museum. Including us.

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