Regulated Battery Supply?

[Alpha579]

Hey all,
I was looking at some schematics, and saw that alot of pedals have 100r resitors in series with +, and a diode and Cap to ground. Does it help to regulate battery power?
Thanx for all input,
Alex

[Transmogrifox]

Yes.  The resistor helps lower the capacitor time constant looking back at the voltage source to increase power supply noise rejection with less capacitance.  The rest of the circuit looks like a current sink, therefore, very high ac impedance, so the capacitor can charge and discharge AC fluctuations on the supply.


the diode is for protection against inadvertent reverse-polarity connection.  No current will flow in the reverse direction.  Another way I have seen the diode is in shunt, therefore, it takes all of the current from the reverse connected battery, keeping the ciruit's reverse voltages to a non-destructive potential.