Best way to measure cathode follower current

[fluckscapacitor]

What is the best way to use a meter to display the bias current for a basic cathode follower circuit? Would it be better to put the meter in series with the plate or the cathode?

 

[Burnedfingers]

You can measure the current several ways. You can measure the voltage across the plate resistor divided by the resistor value to obtain the current flowing. Example... You have 100 volts across a 10K resistor so using ohms law you would come up with .010 or 10mA. You could also measure the current across the cathode resistor and divide that by the value of the resistor to also obtain the current.

Now, if you are asking to put the meter in the circuit and leave it that way I personally have a hard time trying to figure out why you would want to do so. Granted you could put the meter in series with either the plate resistor or the cathode resistor. Sonically I don't know if it would take away from the sound quality. I just don't think I would do it just for display purposes but that is just one opinion in many that may follow.

 

[fluckscapacitor]

Hi,

I don't have a plate resistor for this circuit, I would have to add one and put the meter in parallel with it. This resistor would only be about 2 ohms for full scale on the meter.

 

[Robert McLean]

Putting the meter on the cathode side will be safer from the point of view of the terminal to case voltage rating of the meter. to be real safe put the meter on the ground end of the cathode resistor, not the cathode end. It may be that I am imagining dangers where there are none, and that your ammeter has a high enough isolation voltage rating, and your plate voltage is not too high, but if not then mounting on the plate side could be a problem.