I am new to Arduino and electronics and hoping for some help with a project.

I created a blinking LED by switching high / low through arduino on an output pin connected to an LED. I controlled the blink rate by a potentiometer.

What I would like to try now is turning a transistor that is amplifying audio on and off to produce a stutter effect an the passing audio. I was thinking of turning the collector voltage on and off. The audio transistor is powered by a seperate 9vdc power supply.

I have found this which appeared to at least suggest what I am thinking maybe possible.

http://www.w9xt.com/page_microdesign_pt12_hv_pnp_switching.html

Where the load is connected to the switched 12v I would connect the collector of the npn audio amplifier (9v though).

As the calculations are based on a .5 amp load whereas mine will be just another npn transistor I am at a loss trying to work out the component values.

I really would appreciate help and guidance.

 

Why not use FET/Mosfet, starting with the 2n7000 that was made to interface directly to TTL/CMOS to up to 60v 200ma load or the low voltage gate Mosfets IRL520/530?
Max.

 

Are you trying to turn this on and off with the Adruino or with the audio to a speaker?

 

Max, I am a total noob at electronics so I am just hoping to scape together this project, I have no idea what a cmos is, but I will read up.

The audio is from a seperate source (a sampler), goes into the transistor/pre-amp and then onto a seperate power amplifier.

I know I can fire out 5v on an output pin on the Arduino board, and switch that on and off. I tried using that 5v supply putting it to the collector of the the pre-amp transistor, but the audio became full of weird noise, it did produce a stuttering effect mind you.

So I then wondered if I could use the Arduino 5v out to switch another transistor on allowing a seperate 9v supply to reach the collector of the pre-amp transistor.

Could a relay be fired by the arduino 5v, allowing a 9v to pass on another pole?

 

It's still not clear to me what you are trying to do. Are you trying to make an LED turn on and off to the beat of the music?