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Driving a small (20w) audio amp from a pic output, best way for clear low-mid freq alarm sound?

M

Me

Hi all,
I'm making a kitchen countdown timer ( my first pic project ) for the wife,
who is half deaf and needs a low to mid range frequancy alarm with some UMPH.

Q1. What's the best way to couple a pic output pin to a 20 watt amp?
Q2. Will the amp try to draw too much current from the pin?
Q3. Should I use a transistor switch ( or pair ) to drive the amp?
Q4. Would a line driver be better than an amp?

I need to keep the internal temperature down as low as posible as it's
going in the kitchen.

Thanks for any help.
 
M

Michael Black

Me said:
Hi all,
I'm making a kitchen countdown timer ( my first pic project ) for the wife,
who is half deaf and needs a low to mid range frequancy alarm with some UMPH.
20watts is a pretty big amplifier for this sort of thing.

If she hears that badly, you might try something like flashing a light,
instead. Or a vibrator, though that's not really a suitable solution
here since you'd need the vibrator to be in contact with her, so you'd
need to move to some wireless solution.

Michael
 
J

John Popelish

Me said:
Hi all,
I'm making a kitchen countdown timer ( my first pic project ) for the wife,
who is half deaf and needs a low to mid range frequancy alarm with some UMPH.

Q1. What's the best way to couple a pic output pin to a 20 watt amp?

If it is a normal audio amplifier with a line in jack, a 100
k volume control with one end grounded, and one connected to
the PIC output with a .1 uF or larger cap, wiper to
amplifier input.
Q2. Will the amp try to draw too much current from the pin?

Not if it is a line input. If you are also building the
amp, then it depends on what you build.
Q3. Should I use a transistor switch ( or pair ) to drive the amp?

I think the PIC should be able to drive it.
Q4. Would a line driver be better than an amp?

The amp has to be able to drive the speaker that will
produce the sound. An ordinary audio amplifier should work
fine.
I need to keep the internal temperature down as low as posible as it's
going in the kitchen.

If you build the amp, it can be one with a saturated output
(full square wave) not a linear hi fidelity type. This will
make the amp sound harsh, like a siren, but will make it run
cool.
 
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