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op amps

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Josh

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hi.

if i make an amplifier with an op amp, and just want to use a battery or single power supply, i can connect the negative supply to earth. Does that make the output have a buzzing sound when a speaker is connected? also if i want to make an amp using an opamp with one power supply, but want to power it with + and - 12V is there a schematic i can use to make it? Cheers.

Josh.
 
Hi Josh,

If you go with the single supply (+ volt only supply) make SURE you use a single-supply op-amp. Preferrable a single-supply rail-to-rail op-amp.
 
An opamp by itself doesn't have enough output current to drive a speaker. It needs to drive a complimentary pair of output transistors to boost its output current. The amplifier will have a DC output voltage if it has a single supply and will need an output coupling capacitor to block the DC from reaching the speaker.

Two of these amplifiers can be bridged for up to nearly 4 times more power to a speaker, then an output coupling capacitor is not needed. Many IC amplifiers are made for cars and are bridged. A TDA2005 is a mono bridged amplifier IC and a TDA1554 is a stereo bridged amplifier IC. They produce about 14W RMS at clipping per channel into a 4 ohm speaker with a 13.2V supply. They produce more power (20W) when driven into severe high distortion and a 14.4V supply.

Speaker buzzing? Maybe the amplifier is clipping because its volume control is set too high.

Any opamp will operate fine from a single supply voltage if its inputs are biased correctly. Like this:
 

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miya-sun

Your post is so inappropriate that I expect there is a rule against it on this forum. If there isn't, there should be.
 
miya-sun

Your post is so inappropriate that I expect there is a rule against it on this forum. If there isn't, there should be.

Well, it appears to be deleted, either that or you're talking to your imaginary friend. :p

There should also be a rule against bumping old threads unless it's relevant. :rolleyes:
 
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