Author Topic: Measuring Voltage for a Transistor to Bias  (Read 1213 times)

Timko

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Measuring Voltage for a Transistor to Bias
« on: May 13, 2015, 09:30:47 AM »
I just finished putting the components on my PCB for my Bear Hug Compressor, and there's sound coming out of the circuit, so it looks like I got everything soldered correctly!  However, I need to bias Q1 around 5-5.5V.  Now there's a test pad on the board (and I was wondering why I had a pad that had no component in it :) ), so I assume that I connect one of my probes from my multimeter to that. 

Where do I connect my other lead?  Do I need to have the power on, and a signal going through it to bias?

Here's the schematic is on page 3, and you can see the test pad there: http://1776effects.com/wp-content/uploads/2015/03/Bear-Hug-V2-1.pdf

Thanks all!

Schectadon

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Re: Measuring Voltage for a Transistor to Bias
« Reply #1 on: May 13, 2015, 09:50:23 AM »
black lead to ground, red to test pad, Multimeter set to vdc. turn trimpot until voltage it in the required range.
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lincolnic

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Re: Measuring Voltage for a Transistor to Bias
« Reply #2 on: May 13, 2015, 09:30:40 PM »
You do need power to the circuit, but you don't need to have any signal running through it.

Timko

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Re: Measuring Voltage for a Transistor to Bias
« Reply #3 on: May 14, 2015, 07:35:08 AM »
I figured that I needed power last night when I did my readings and got nothing :).  Thanks!  I got the resistor biased correctly, so now it's time to drill and paint and enclosure for it.