I have some knowledge of how opamps work in a audio-driver application.. But a recent project im attempting has me scratching my head.
Part of this circuit has an op amp and transistor based feedback that works to control 2 led outputs. One red and one IR. And using data from a light to frequency sensor, the MCU controls a dual output DAC which gives output to two op amps which is connected to some transistors... connected in a fashion i dont really understand, thus controlling the IR led's output to match the Red led's output. I could easily copy the schematic for my needs but i want to understand how it works.
On the code side of things, the microcontroller turns each led on and off, takes freq samples from the FTL and compares their frequencies and steps up or down the value to send to the DAC until the outputs match.
Thanks for any help trying to understand what the point of the quad-transistors are for.. Detail is what im looking for..
Some more info.. VB is the 9v source and Vdd is the 5v source. The MCP4822 is the DAC RB0 and RB1 are connected to the MCU