I'm new here and possibly well outside my general electrical knowledge area so any help would be appreciated. I am attempting a very simple circuit to boost a 9vdc remote on signal to a 12vdc signal for an audio amplifier. I don't know why my factory amp takes only 9vdc to turn on, but I have an aftermarket one that requires 12vdc to turn on and it would be nice if I could use the factory wiring so I don't have to run any new leads anywhere. I thought a comparator op amp would be perfect, but I don't know how to set the circuit up. I have a 12vdc for the +Vcc on the op amp and ground for the reference and -V . Idealy, when the 9vdc signal is applied to the input Vin>Vref the Vout should be +Vcc or 12vdc. I'm not worried about current capacity because it's only a signal line (idealy infinite impedence).
Now I get to admit how stupid I am. I got a LM339 quad comparator op amp from RadioShack and a little IC board, soldered the chip to the board and then some wire terminals to the chip leads. I then tested it without attempting to hook anything into my car by using three 6vdc batteries. I put 2 in series for a 12vdc +Vcc and connected the - terminal of the third in parallel for a common ground. I connected the common ground to pins 4 and 12 to give a 0vdc ref signal for the op amp. I then connected the 12vdc + to pin 3 for the +Vcc. Now I connect the 6vdc + to pin 5 for the Vin signal and should get 12vdc on pin 2 Vout. Instead I get 0. What am I missing?
pinout of 339 IC chip is:
pin 1 OUTPUT 2 (there are 4 comparator op amps on this one chip)
pin 2 OUTPUT 1
Pin 3 V+ (+Vcc?)
Pin 4 INPUT 1 -
Pin 5 INPUT 1 +
Pin 6 INPUT 2 -
Pin 7 INPUT 2 +
Pin 8 OUTPUT 3
Pin 9 OUTPUT 4
Pin 10 GND
Pin 11 INPUT 4 +
Pin 12 INPUT 4 -
Pin 13 INPUT 3 +
Pin 14 INPUT 3 -
Also, can anyone double-check me that I'm counting the pins correctly? Looking from top of the chip pin 1 is top left if the U-shape cutout is at the top.
Thank you for your assistance
Now I get to admit how stupid I am. I got a LM339 quad comparator op amp from RadioShack and a little IC board, soldered the chip to the board and then some wire terminals to the chip leads. I then tested it without attempting to hook anything into my car by using three 6vdc batteries. I put 2 in series for a 12vdc +Vcc and connected the - terminal of the third in parallel for a common ground. I connected the common ground to pins 4 and 12 to give a 0vdc ref signal for the op amp. I then connected the 12vdc + to pin 3 for the +Vcc. Now I connect the 6vdc + to pin 5 for the Vin signal and should get 12vdc on pin 2 Vout. Instead I get 0. What am I missing?
pinout of 339 IC chip is:
pin 1 OUTPUT 2 (there are 4 comparator op amps on this one chip)
pin 2 OUTPUT 1
Pin 3 V+ (+Vcc?)
Pin 4 INPUT 1 -
Pin 5 INPUT 1 +
Pin 6 INPUT 2 -
Pin 7 INPUT 2 +
Pin 8 OUTPUT 3
Pin 9 OUTPUT 4
Pin 10 GND
Pin 11 INPUT 4 +
Pin 12 INPUT 4 -
Pin 13 INPUT 3 +
Pin 14 INPUT 3 -
Also, can anyone double-check me that I'm counting the pins correctly? Looking from top of the chip pin 1 is top left if the U-shape cutout is at the top.
Thank you for your assistance