op amps

[Josh]

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.

 

[Brocktune]

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.

 

[Brocktune]

Like this one:

https://www.electro-tech-online.com/custompdfs/2003/07/LM6142.pdf

 

[gramo]

is the 6142 a good op-amp, or are there better single-supply rail-to-rail op-amp?

 

[gramo]

What I need is an op amp with a single single supply (+5v) that can produce accurate results with 10mV to 1V inputs running a gain of 5.

 

[audioguru]

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:

 

[bychon]

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.

 

[Hero999]

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.

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

 

[AlainB]

miya-sun, from China. Join today, ...already banned!