op amp Trouble transferring schematic (working) to actual circuit (not working)


Posted on Feb 6, 2014

Red = V+, Black = V-, Green = GND, Yellow = Mic Input, Orange = LED Output. The op-amp I`m using is an LM741. It`s supposed to change the peak brightness of the LED depending on the ambient sound level. The frustrating thing is that the simulator is happy with it, but on the board, the op-amp can`t even keep its inputs at the same voltage (4. 4 V difference). The voltage drop on the resistors is wrong too,


op amp Trouble transferring schematic (working) to actual circuit (not working)
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and I think that`s caused by the former. do you have the schematic of the Falstad cct. Asking people to look over odd nodal netlists is akin to asking them to eat glass for you. ;) placeholder Apr 23 `13 at 0:31 A fatally fatally fatal problem is that IF the microphone is high impedance then the opamp is trying to place 1. 7V across the LED. What this does depends on the LED type. If the microphone has a DC resistance of close to zero (moving coil) then Vout will be close to zero. Above that the mic DC resistance will affect the DCout setpoint.




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