Author Topic: 5 Transistor ESR Meter Design  (Read 133827 times)

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Offline mauroh

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    • Mauro Pintus
Re: 5 Transistor ESR Meter Design
« Reply #200 on: September 06, 2018, 12:55:55 am »
Can you please post a picture of your board?

As I wrote, to save the already etched board you can forget abou the silkscren and since there are no components with more than 3 pins you can easily mount all the components on the copper side, or bend the pins of the transistors and mount the voltage regulator facing down.

You don't like this solution?

Mauro

Online m3vuv

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Re: 5 Transistor ESR Meter Design
« Reply #201 on: September 06, 2018, 09:26:06 am »
i think ive sorted it,ive used the unmirrored pcb track layout with the un mirrored silkscreen,im just waiting for the board to etch,ill keep you posted cheers,m3vuv 73
 
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Offline karchiba

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Re: 5 Transistor ESR Meter Design
« Reply #202 on: October 23, 2018, 10:29:35 am »
Good afternoon all,

I have built Jay_Diddy_B's original circuit, on a perf-board, and it seems to be measuring very well with test resistors and known capacitors.

I do have one issue that I'm trying to understand...

When the DUT terminals are left disconnected, there is ~10uA of idle current going through the meter.
I assume it is my choice of diodes D1 and D2... I used 1N4003's, which have a reverse leakage current of 1.1uA, and a Forward Voltage of 0.63v.  I am assuming that these Diodes are used to dissipate voltage which may be contained in the DUT.

I have looked at the graph that the designer (THANK YOU Jay_Diddy_B, it's fantastic!) created, and it does seem that his numbers do show some idle current flowing through the meter.  I also looked at the video that W2AEW created, which was extremely helpful to understand how the circuit worked, and it did show some current without a DUT.

Any suggestions as to a better component choice for the diodes?
Could these be the source of the voltage difference off the bridge which could be showing as the 10uA that I'm measuring?   
Does this 10uA of idle current compare with other builders of this circuit?

Thank you all!  I really am enjoying this build.

_karchiba

 


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