Simple Component Tester (Octopus)

[amr2]

Hello

I built this simple component tester, based on the HAMEG HZ65. It's very simple to build, and it performs quite well. If anyone is interested, this is the original Hameg service manual, schematic included.

 

[labjr]

Interesting. I want to build one of thse devices but there are so many different variants of the circuit. I'm wondering what you changed or added from the original circuit? How does it work for you? Thanks

 

[amr2]

Interesting. I want to build one of thse devices but there are so many different variants of the circuit. I'm wondering what you changed or added from the original circuit? How does it work for you? Thanks

Hello! It works well. I didn’t change anything from the original design.

 

[audiotemp]

Hello! It works well. I didn’t change anything from the original design.

I was impressed (and pleased) to find your link to the Hameg manual still working!

 

[labjr]

Thanks for your reply. Your build looks nice. I have a couple other questions. Is that a rotary switch on the front for the current switch in the original circuit?


Is that a 1 Meg potentiometer or trimmer in the picture?

 

[amr2]

Is that a rotary switch on the front for the current switch in the original circuit?

Yes, it is.

Is that a 1 Meg potentiometer or trimmer in the picture?

It is an internal trimmer to adjust X and compensate it with Y

 

[labjr]

Was HZ65-3 was the last version made? There were some changes made to the circuit. Do you what was the value of this cap? Thanks.

 

[amr2]

100pF

 

[audiotemp]

My guess would be that "a. r." means "as required". The optimum value would seem to depend on the setting of the potentiometer as well as on the length of cable connecting to the oscilloscope.

That is assuming the capacitor compensates the effect of the cable and load (scope input) capacitance on (mainly) the phase response but maybe there is some other purpose to it that I don't see.