EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: strawberry on March 12, 2022, 08:36:25 pm
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1mohm ... 100ohm range
20mV OCV
~1% accuracy or better
4dig display
TH parts
card edge connectors
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so what is the point of the post,are you asking something?,otherwise seems a waste of eev bloggs server hd space!!
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Hi,
That is one of the PCBs from this meter:
(https://www.eevblog.com/forum/projects/esr-meter-adapter-design-and-construction/?action=dlattach;attach=1098782;image)
It is this board:
(https://www.eevblog.com/forum/projects/vintage-esr-meter-kit-project/?action=dlattach;attach=1437691;image)
Image taken from here:
https://www.qsl.net/n9zia//hp4328a/index.html (https://www.qsl.net/n9zia//hp4328a/index.html)
Are you making a similar unit with a digital display?
The original version of the HP4328A works at 1kHz.
Regards,
Jay_Diddy_B
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so is it an esr meter or not?
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so is it an esr meter or not?
Hi,
It as an AC milli-Ohmmeter, it is capable of measuring ESR, but at a frequency of 1kHz. It uses sine waves and a synchronous rectifier to measure the in-phase component of the impedance.
It was designed by YHP. YHP was a joint venture between Hewlett Packard and Yokogawa. A lot of HP LCR meters, like 4274A and 4275A were designed and built by YHP. You can see a slight differences in style and component choices between YHP and HP instruments.
The HP 4328A uses transformers to couple the drive signal and the measurement.
Regards,
Jay_Diddy_B
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It looks like a recreation of the original Phase Sensitive Amplifier PC board 4328A-7022 ? Tape and all. Maybe as a non-fungible token ;)
I don't think you would do a remake of the whole instrument- it has many custom magnetics (4 transformers), 11 axial tantalums are expensive, 14 ECN's, Q206 dual transistor HP 1854-0221 a bit expensive and rare too. Lots of work and then the 1kHz limitation might be annoying.
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It seems to me the 1 kHz operating frequency sets the lower limit of capacitance rather high. 159uF is 1 ohm at 1 kHz.
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It looks like a recreation of the original Phase Sensitive Amplifier PC board 4328A-7022 ? Tape and all. Maybe as a non-fungible token ;)
I don't think you would do a remake of the whole instrument- it has many custom magnetics (4 transformers), 11 axial tantalums are expensive, 14 ECN's, Q206 dual transistor HP 1854-0221 a bit expensive and rare too. Lots of work and then the 1kHz limitation might be annoying.
found modern replacements for reasonable price
yes it seems more expensive than 5transistor esr meter
It seems to me the 1 kHz operating frequency sets the lower limit of capacitance rather high. 159uF is 1 ohm at 1 kHz.
phase detector might compensate both lead and lag angles
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Hi,
At 1kHz the HP4328A works well.
Here I am measuring a 100uF 50V KY series capacitor from United Chemi-con.
Measured on an HP4274A:
(https://www.eevblog.com/forum/projects/vintage-esr-meter-kit-project/?action=dlattach;attach=1438483;image)
and on the HP 4328A:
(https://www.eevblog.com/forum/projects/vintage-esr-meter-kit-project/?action=dlattach;attach=1438489;image)
There is good agreement between the two instruments. Both measurements were made at 1kHz.
Jay_Diddy_B
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so what is the point of the post,are you asking something?,otherwise seems a waste of eev bloggs server hd space!!
Don't worry, we have plenty of it :)
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looks like a major hard project,verging on the near impossible to finish due to eol parts etc,hats off too you if you pull it off.
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circuit modification for better temp stability
probably 2% is lost in these parts: CR207, CR208, Q209, Q201, Q202