jay diddy 5 transistor esr meter

[pete g]

I checked all the voltages on the amps. the voltages are correct. not to sound redundant, but signal at the probes is correct, so it appears everything is correct but I still get full scale deflection at tutn on with the probes open?che pasa?

[pete g]

thanks dannyf, I think it makes more sense to me. what should the voltages be when the probes are shorted?

[Jay_Diddy_B]

Hi,
If the probes are shorted you will have the following conditions:

All the DC voltages marked in this schematic will remain the same.



TP1 will be ground.

There will be no ac voltage on Q4 base and no ac voltage on Q4 collector.

Can you tell me what kind of diodes you used for D3 and D4?

What kind of meter are you using?  Do you have the model number or a link?

What do you have in series with the meter?

Can you post some photographs of your construction?

Regards,

Jay_Diddy_B

[pete g]

hi jay, well, thanks to dannyf, the problem is solved. it seems my 78 year all eyes (good excuse as any) let me down. it cleary shows r11 in the bridge circuit should be 1.5k, not 15k. the esr meter works perfectly. so, thanks are in order. jay, thanks so much for taking the time to help. to all who contributed, thanks again. I'am so happy!!!!!

[Jay_Diddy_B]

Hi Pete,

That is great news !!

It would be great if you can post a picture of your finished meter.

Regards,

Jay_Diddy_B

[pete g]

I will post a picture of the finished meter.

[pete g]

Here is a picture of my finished esr meter by jay diddy b.  Nothing fancy but it works.

[Bryan]

Very good job on the artwork for the meter faceplate

[pete g]

thanks, bryan. actually my wife is responsible for it.

[Bryan]

She did a great job. Found this software that can do panel meters.

http://www.tonnesoftware.com/meter2.html

[pgr2002]

Does anyone know if the circuit can handle 1ma meter instead of 50ua.  If so what changes should be done in the circuit to handle 1ma panel meter. What can be the value of R24 which is marked x in the circuit diagram.

[pgr2002]

Hi,
If the probes are shorted you will have the following conditions:

All the DC voltages marked in this schematic will remain the same.



TP1 will be ground.

There will be no ac voltage on Q4 base and no ac voltage on Q4 collector.

Can you tell me what kind of diodes you used for D3 and D4?

What kind of meter are you using?  Do you have the model number or a link?

What do you have in series with the meter?

Can you post some photographs of your construction?

Regards,

Jay_Diddy_B

I would like to construct this circuit.  But I have 1ma meter panel and 2 analog multimeters.  What changes can be done to use this 1ma panel meter in the circuit.  Also in the circuit diagram I saw R24 marked x.  What is the value of this R24 (range). Will this change with different meters viz. with 50ua what can be the value and with 1ma meter what value to be used.

[Jay_Diddy_B]

Hi,

Sorry for the delay in responding.

The use of a 1mA meter has been discussed in the main thread for this project.

link: https://www.eevblog.com/forum/projects/5-transistor-esr-meter-design/msg3328450/#msg3328450

Regards,
Jay_Diddy_B

[pgr2002]

Hi Pete,

That is great news !!

It would be great if you can post a picture of your finished meter.

Regards,

Jay_Diddy_B

I am having the same problem just like Mr. pete had.  When the circuit is switched on the meter (50ua) needle goes far right and even overshoots.  And when the leads are shorted it comes down to 90% of the scale to the left.  What can be the problem here. The diodes used by me is 1n4148 and 1n5711

[Jay_Diddy_B]

I am having the same problem just like Mr. pete had.  When the circuit is switched on the meter (50ua) needle goes far right and even overshoots.  And when the leads are shorted it comes down to 90% of the scale to the left.  What can be the problem here. The diodes used by me is 1n4148 and 1n5711

Have you checked the dc voltages that are given in the schematic?

Do you have an oscilloscope? Can you share some waveforms?

You can watch this video by W2AEW, that shows the circuit working.

Link:

Regards,

Jay_Diddy_B

[pgr2002]

I saw the video of the workings.  I don't have oscilloscope.  I am using the 5v adapter to the circuit.  I am getting almost the similar voltages except that it is little more.  I don't understand why the meter goes to the far right when switched on and when the probes are shorted it comes back to the left to 10 on a 50 meter scale (50ua meter).

[pgr2002]

Well this works fine.  The capacitor marked c8 valued at 22n is bad in my circuit.  After rechecking all the points I found that this capacitor is open.  I didn't have 22n but replaced with 0.01uf and the circuit started to work perfectly.  Thank you Sir,  This just
works splendid.  I just worked in breadboard, shortly I will make a pcb.  The only thing is the meter will be kept outside the box, since I have 2 panel meters (50 & 100 ua), the rest will be enclosed including power supply. The original values of caps and resistors will be replaced once I get these from the market.  The resistor of 3E (R10) is not available right now, but tested with 2.2E. The rest of parts are as mentioned in the circuit. I checked few capacitors and is giving good results.  Thank you once again.

[thejazzcat]

Hi,

I'm building the tester using my Simpson 260 50uA Meter. But I can get full deflection when shorting the test leads.

Attached photos of the oscilloscope readings shared bay Jay_Diddy_B for troubleshooting. I'm not getting a Square Wave on the Collectors of Q4 and Q5. The oscillator freq. is lower in my unit (around 90KHz).

Any pointers on how to proceed would be much appreciated.

All the best.
CE

[Jay_Diddy_B]

Hi,

I'm building the tester using my Simpson 260 50uA Meter. But I can get full deflection when shorting the test leads.

Attached photos of the oscilloscope readings shared bay Jay_Diddy_B for troubleshooting. I'm not getting a Square Wave on the Collectors of Q4 and Q5. The oscillator freq. is lower in my unit (around 90KHz).

Any pointers on how to proceed would be much appreciated.

All the best.
CE

thejazzcat and the group,

Generally speaking, if the dc voltages are correct, the problem is with one or more of the capacitors.
Check the 2.2uF capacitors in the emitters of Q4 and Q5. If you have to use an electrolytic capacitor, you can use a much larger value 47 to 100uF 6.3V or greater.
Also check the 10nF and 22nF capacitors.

Jay_Diddy_B

[thejazzcat]

Thanks Jay_Diddy_B.

I was using the wrong caps in place of the 2.2uf. Ended up using a couple of 100uf 25V I had at hand (following your recommendation on electrolytics) and now I'm getting the correct deflection on the meter. R24 value is going to be around 15K ohm.

I still need to buy the pot to finish the project.

You are so kind to share your knowledge on this forum.

Thanks mate.

[p.larner]

i used a 1ma meter in one i built,if i remember i changed a few resistors as mentioned in the thread linked but had to power it with about 11v not 5v.