Led indicator in solid state amps
Hello everyone. I have a pretty simple question. After looking at a lot of schematics, I've noticed that some placed the inicator led between the +/- power rails and some place it between the + rail and ground. Why? Is one way better than the other? I've built a solid state amp that has a tda7294 chip amp in the output and uses a split rail (+/-) supply. Any help would be apreciated.
- thetragichero
- Breadboard Brother
it shouldn't make much difference as long as you have a proper current limiting resistor in there (sometimes I can forget that a +/-15V supply is a 30V supply kinda thing)
- deltafred
- Opamp Operator
The advantage to putting it across the +/- supplies is that it acts as a monitor so if it fails to light or is dim then you know something is wrong with the supply rails. If it is across the + only then the - rail can be faulty and it will still light normally.
The slight disadvantage is that more power is dissipated in the current limiting resistor.
The slight disadvantage is that more power is dissipated in the current limiting resistor.
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Jeez, she's an ugly bastard, she makes my socks hurt. I hope it's no ones missus here. - Ice-9 2012