I took this TO-18 transistor from a russian made microphone that was used in a toy car, ambulance hand clap commanded.
I had this component from when I was a kid, and misteriously damaged the car. Great toy, forever in my memory.
Anyway... I had this michrophone thrown away in the box and today I said to open it up and see whats inside, because it was a bit too big for a simple microphone.
And this transistor was hooked up inside, next to the microphone. And it had 3 wires to it, whats why it sparked my curiosity.
You can count 4 legs on this tr, one is already cut from factory.
I tried to measure with DMM on diode to check if its PNP or NPN and I couldnt figure it out like that. SO I unsolder it and put it to my tr tester there to be shocked to my core that is not showing any tr reading. Yes I repeated several tests, in the case this was my device bugging out but it was a consistent reading like the one in the picture.
One of the legs was too short to insert it into my tester so you can see I soldered a small piece of wire to help it connect properly.
It's markings is a CLEAR: AB0 ...or ABO ...or that B is a russian V? so AVO or AV0 ?
I searched on www and nothing.
It was using 4 big fat batteries... so it must have been some 6V probably to power the entire board which was big and complex. It was quite a big toy, I remember I was carrying it with my arm around it as a child, and that was it's end.
Probably like that D model. They hold like a week or so. I remember I couldn't permit to change its batteries for a very long time. Thats why I "looked" inside it, probably as a child.
- What do you think? is this a bad transistor? Or its a very weird component?
- In my experience, when I was testing literally Hundreds of scrapped transistors -long ago- , some of them I remember were showing this kind of diode reading (not exactly like this but some configuration of diodes). I throw them away or I think I store some of them in my miscellaneous diode drawer, to use them in the future, to confuse everyone and everything on what the hell that cct is doing...hahaha.

 

It could be a FET and hence would not check out as PNP nor NPN.

 

This tr tester can see FET's. Is no problem.

 

Because I could't properly measure this tr, I really dont know what it is so I IMAGINED the circuit it MIGHT have been like this. Let's say its a NPN. And the MIC might be on its base. Only these 2 components were put in a aluminium tube case and 3 wires from it. So on the big board they were processed.
I expect someone should jump up if this is correct or not. If is probable.

 

It is more likely a FET if it was packaged with the mike capsule. The ones you buy today have the FET inside the capsule, but an older Russian one, who knows?

Electret mikes pretty much need the high impedance of a FET amplifier to operate. Unlikely it would be connected directly to the base of a BJT.

Did you try multimeter diode test?

 

Did you try multimeter diode test?

I mentioned already, it was the first thing to try, then I took it out and inserted into tr tester.

 

The hole of the tr


The mic with 2 legs

I also can see now a resistor ... 7k5? I cant get out the mic, it has some blobs of solder on its legs on the other side.

The aluminium can in my fingers - pretty big.

 

It is electret microphone

 

It is electret microphone View attachment 328934

WOW - thats exactly it. I also have the rubber shirt over the aluminium can. You perfectly nail it !
Ok... How can I test it if it's even good ?
I will put back the transistor and wait for a test cct.

Is very good that I made a wiring diagram before taking out the tr.
I put it back as it was now, voila:

 

Use 3 V PS.
+ (common) = blue or black or green.
- = red or brown.
OUT = white or yellow or orange.
Connect oscilloscope probe x1 to OUT, ground clip to + 3V,
then speak something and see on screen.

 

(with your 3V suggestion)
Here is my interpretation:

 

I made your test ! Thank you very much! I think it works !
I had to blow air over mic to see the waveform. By simply talking, it didn't catch it.
The waveform was very noisy when I was blowing air into mic. And it stopped when I wasn't blow air. I conclude that it works.
Now.... the next challenge ! I have 2 spare and scrapped speakers.

Lets make a very simple amplifier for this microphone and output the sound on one speaker.
I am very rookie at sound electronics, so I will follow your cct exactly.