Measuring and Reporting Transistor Voltage

[iiimonfire]

Hi all,

First time poster, long time reader.
Apologies for the noob question (not an EE, but have a background in signal processing), but I can't seem to find a straight answer for this.

What does it mean to measure the voltage across transistor pins, and how do I go about doing this with my DMM?

I ask because as I find myself troubleshooting my first builds, I see many requests for support on this forum in which people post these measurements.

An example of the kinds of measurement data I would like to know how to provide, in the format I typically see here:

Voltage:
Q1:
c=8.75
b=0.73
e=0

Q2:
c=9
b=1.66
e=0.73

D1:
A:0
C:0


Sent from my iPhone using Tapatalk

[amz-fx]

What does it mean to measure the voltage across transistor pins, and how do I go about doing this with my DMM?

Power up the pedal but no audio signal going through it. Negative (black) probe on a ground point. Positive (red) probe used to test the DC voltage at the various points of the circuit that you want to measure.  Recording the DC voltages is the best way to get started in troubleshooting a pedal (after a visual inspection).

The voltages will tell you (and us) the operating conditions of the idling pedal, and the readings can be compared to typical voltages that would be expected at those points. It can reveal reversed transistors or diodes, poor connections, and more.

regards, Jack

[iiimonfire]

Awesome! Thanks for the quick response, Jack!

Will definitely get to testing as soon as the weekend rolls up

[antonis]

@ Daniel: Jack's prompt

Power up the pedal but no audio signal going through it.

doesn't mean to test your pedal WITHOUT input jack plugged.. 

(it's very common mistake - not only for beginners..)