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October 03, 2025, 07:03:56 AM

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Dude..... where's my voltage

Started by saturated, August 29, 2025, 04:16:59 PM

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saturated

So I think I built my first amplifier

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Is it clear now  :lmao:

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I input a one khz signal and measuring at the collector I get amplified voltage ? 

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But it's out of phase so measuring at the emitter it's in phase but I lost all my voltage
 :grr  :-X  :'(

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And I know there's reasons for all of this so I'm off to learn about it.

I have a suspicion calculating and looking at the voltage drops and voltages will explain much of it.

 xP

I ask stupid questions
and make stupid mistakes

criticism, critique, derision, flaming, verbal abuse welcome

J M Fahey

#1
Yes, 6X gain (6.8/1)

That´s a classic transistor gain stage; my classic go-to value with 10k load  is 3M3 bias or for 3k3 or 4k7 load,  1 M bias.
Works all the time with almost any transistor.

Gain is load resistor value divided by emitter resistor value.

Works fine up to 50X gain, go figure.

Back in the day I published in a Magazine a series of projects based on these. from a single transistor Guitar booster up to a 6-8-12 channel mixer.

Lots of people built them and a few work to this day.

saturated

Senor JMH mucho gracias for accompanying me on this venture.
  I have some more snacks for you amigo  :tu:

I was to calculate then measure the maximum peak to peak output voltage by increasing input until clipping occurred

So I did it maxed out about 20 Vp-p

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Any slight increase and ...

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This reminds me of you big dogs 🐕 telling people to adjust trim pots ?  until clipping occurs

Anyhow Happy Labor Day everybody  :tu:
I ask stupid questions
and make stupid mistakes

criticism, critique, derision, flaming, verbal abuse welcome

Jazz P Bass

Is the input capacitor installed 'backwards'?

saturated

Yes sir thanks idk

I struggled with the orientation and looking at the schematic I did not know what the curved line of the symbol indicates but after some research I thought it was supposed to be the negative terminal

 :loco
I ask stupid questions
and make stupid mistakes

criticism, critique, derision, flaming, verbal abuse welcome

g1

Yes, curve is negative.  Looks like base is positive so I think cap is shown correct on schematic.
Maybe Jazz was wondering about your wiring?