EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: The_Todd on November 03, 2018, 08:06:41 am
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Hello guys,
I got this at the tip shop, as it piqued my Curiosity. There is absolutely not markings or stickers or anything. The 2 switches on top are 3 position high middle and low. If i put the multimeter in beep mode and hook up the arm swings so I’m guessing its a low amp testing device. However this happes whether there is power or not..... hmmm
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Judging by the Cx and the letter 'p' written on the front panel, it suggests it's a capacimeter.
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Judging by the Cx and the letter 'p' written on the front panel, it suggests it's a capacimeter.
Well that would be great, dont have one of those lol. also this looks like its was meant to be mounted on a wall or somthing, not made to sit on the bench at all. Perhaps this is a test device in some bigger device or factory setup?
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Seems to be capacitance bridge (meter). http://conradhoffman.com/cap_bridge.pdf (http://conradhoffman.com/cap_bridge.pdf)
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Hi!
Look in the September 1976 Issue of the UK's "Practical Television" magazine (free from American Radio History site) and there you'll find construction plans for exactly the sort of instrument you've shown, based on a 555 timer chip!
The capacitor is periodically charged and discharged by the 555 and by integrating the area under the voltage – pulses with respect to time over the pulse duration (Vc = 1/C x integral v.dt) the meter will read the average current, which can be shown to be directly proportional to the value of C – a short appendix is provided showing the formulae!
Chris Willlams
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Hi!
Look in the September 1976 Issue of the UK's "Practical Television" magazine (free from American Radio History site) and there you'll find construction plans for exactly the sort of instrument you've shown, based on a 555 timer chip!
The capacitor is periodically charged and discharged by the 555 and by integrating the area under the voltage – pulses with respect to time over the pulse duration (Vc = 1/C x integral v.dt) the meter will read the average current, which can be shown to be directly proportional to the value of C – a short appendix is provided showing the formulae!
Chris Willlams
Wow great find I look this up, thanks again. So what exactly is this thing used for?
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