1w Amp Q.

wmmullaney

New Member

• Nov 7, 2007

• #1

Hi, can you tell me if this schematic will work? (with 1 transistor, not darlington)

https://sci-toys.com/scitoys/scitoys/computers/solderless/1_watt_audio_amplifier.jpg

 

M

mneary

New Member

• Nov 7, 2007

• #2

A darlington is required. It will sound terrible and run the battery down very quickly.

If that's what you call "working" then yes.

 

wmmullaney

New Member

• Nov 7, 2007

• #3

OK, thanks.

 

audioguru

Well-Known Member

Most Helpful Member

• Nov 7, 2007

• #4

The simple circuit is a joke. It won't produce anywhere near 1W into an 8 ohm speaker.

The 50 ohm resistor will reduce the max power into an 8 ohm speaker to only 21mW if the darlington transistor is biased correctly (it isn't). I simulated the circuit and the 8 ohm speaker has a max signal power of only 5mW. Its DC power is 85mW.

The battery current is 103mA so it won't last long.

 

wmmullaney

New Member

• Nov 8, 2007

• #5

Any ideas how to fix this? I don't want more part than are shown)

 

audioguru

Well-Known Member

Most Helpful Member

• Nov 8, 2007

• #6

It is not an audio power amplifier It is crap.
An audio power amplifier circuit needs at least 3 transistors, two diodes, four capacitors and some resistors to make a much better but still poor quality audio power amplifier.

Use an audio power amplifier IC instead. Hundreds are available. Their quality is good to excellent and they are inexpensive.

 

wmmullaney

New Member

• Nov 8, 2007

• #7

OK, I'm going to order 3 or 4 lm386's to play with. Thanks.