Optocoupler Circuit Overheating
Posted: Sat Sep 03, 2016 4:32 pm
I must be missing something. I tried to design a simple Optocoupler circuit. I have a 24V power supply which powers a 7805 Voltage Regulator. A simple switch powers the Optocoupler. I have a delay timer (555 timer) in between the input and the output Optocouplers.
I put this on a breadboard, but when I leave the input pushbutton pressed, the 7805 Voltage regulator gets very hot, very quickly. The circuit performs the function that I expect, but I didn't think I would draw that much current, as the 7805 is rated for 1.5A.
What can be drawing so much current that the regulator cannot supply the required voltage? What have I messed up in this circuit?
The attached image shows the circuit. NOTE: Everything in orange is the bottom layer of the PCB design, which is all ground.
DJ
I put this on a breadboard, but when I leave the input pushbutton pressed, the 7805 Voltage regulator gets very hot, very quickly. The circuit performs the function that I expect, but I didn't think I would draw that much current, as the 7805 is rated for 1.5A.
What can be drawing so much current that the regulator cannot supply the required voltage? What have I messed up in this circuit?
The attached image shows the circuit. NOTE: Everything in orange is the bottom layer of the PCB design, which is all ground.
DJ