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Test Equipment Identification needed

 
Jamie
(@jskinner97)
Noble V-Ratter Registered
Posts: 1601

Recently got a job lot of mainly

components, assorted tat and a few others bits. These two were among them… 

 

Any ideas what they are/do?

 

The latter seems to be a home brew 

635D0BA7 BCDE 40CB 8CA2 056A2B7B161E
D7A067BB EFB4 4291 A5A2 BCEC0868FB3D
D96923C9 8A67 4DD1 AF4A 6E877FDBB1D4

 

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Topic starter Posted : 03/07/2022 6:36 pm
crustytv
(@crustytv)
Vrat Founder Admin
Posts: 11044

Honest answer is I don't know.

I don't think these are the usual types of devices you'd find in a standard Radio/TV workshop, the only tenuous link is the Rank connection to one device. The bottom unit, Rank Nucleonics, lab device?

The top one as you already suggest is home-brew, look at the god awful components (diodes/resistor?) on long legs! Who would construct like that! Look how they are all leaning over, potentially shorting to one another, I'd not power that up, in that state.

It's a shame @valvebloke does not visit us any longer, I'd lay odds on, he might have a good indication of the bottom device's function, considering his background.

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Posted : 03/07/2022 10:33 pm
Marconi_MPT4
(@marconi_mpt4)
Reputable V-Ratter Registered
Posts: 354

The DC Amplifier is an interesting piece of test gear clearly aimed for laboratory use as it has settings for measuring very low input levels of current (x10^-12 amp) i.e. pico amps, and charge Q (x10^-10) possibly could be 0.1μC.

I suppose this could be regarded as an electrometer characterised by high sensitivity allow it to make voltage, current, and charge measurements which are not available on a standard DMM. For charge measurements the input impedance is extremely high so as not to discharge the source.

Keithley Instruments now owned by Tektronix published a guide to low level measurements that might be a useful introduction.

https://www.tek.com/en/documents/product-article/keithley-low-level-measurements-handbook---7th-edition

Rich

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Posted : 04/07/2022 3:45 pm
Jamie
(@jskinner97)
Noble V-Ratter Registered
Posts: 1601
Posted by: @marconi_mpt4

The DC Amplifier is an interesting piece of test gear clearly aimed for laboratory use as it has settings for measuring very low input levels of current (x10^-12 amp) i.e. pico amps, and charge Q (x10^-10) possibly could be 0.1μC.

I suppose this could be regarded as an electrometer characterised by high sensitivity allow it to make voltage, current, and charge measurements which are not available on a standard DMM. For charge measurements the input impedance is extremely high so as not to discharge the source.

Keithley Instruments now owned by Tektronix published a guide to low level measurements that might be a useful introduction.

https://www.tek.com/en/documents/product-article/keithley-low-level-measurements-handbook---7th-edition

Rich

Thanks for that, and you're exactly right.. Someone on facebook said:

"The DC Amplifier was a common thing before digital multimeters and a sort of "replacement" for galvanometers (the really sensitive ones could be very fragile). It allowed you to connect a sensor (a thermocouple, oxygen sensor, geiger tube) that give really low outputs (think along the lines of thousandth of a volt) and 'translate' that to an analogue display that could be read - the dial on the left. The rotary control adjusts the sensitivity of the amplifier - like the range selection on a multimeter. It was also likely calibrated annually by an instrument technician so it's readings were reliable and consistent."

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Topic starter Posted : 04/07/2022 7:01 pm
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