[SOLVED] Question about power supply decoupling

[obrien135]

Hello again,

My question this time is:

If you choose a decoupling inductor that has a high reactance at the frequency of operation, in comparison to the output impedance (perhaps the collector resistance of a common emittor or common base amp), would it attenuate the signal significantly?

George

 

[betwixt]

If it is in series with the signal, yes. If you are using it to block the signal but let DC through, no, it will isolate the DC components and probably give more signal.

Think of it as a resistor with a different value at DC to at your signal frequency. To DC it will only be a few Ohms because of the copper wire resistance but to RF it's apparent resistance will be 2*pi*f*L where L is the chokes inductance and f is in Hz.

Brian.