OK Bob...I thought that was you that was testing a commercially made active bias years ago. It might have been your prototype.
But as far as testing the bias..... The voltage and current has been tested under load. I have a steady voltage and current is limted. There is really nothing else I can check on the bench. I was actually going to just keep it set at 200ma and just put a fuse in series with the ammeter when I test it in the amp. I have a small value resistor and diode just before my rf choke. The diode will function as a clamping diode.
Thanks for mentioning it Bob.... that could have been easily forgotten/overlooked.
But if I can set the voltage at .7 volts or so....... and my current is limited to around 200ma ( will be variable when I test so I can start lower)...and i have a fuse in series with the bias output. ... why not test it in the amp.
I can monitor the bias current, bias voltage, amplifier current. I can increase the bias current/voltage as needed. I just want to get enough voltage and current to turn on the base. Once I have low voltage/current applied to the base I can generate rf in at low power... monitor the bias current...amp current..and bias voltage while checking out the waveform.
I just need the right amount of current and voltage to turn on the base...and some measures in place to protect it from over current draw. Once I have a steady .7 volts ( or so) going into the base and the current is limited and protected.....I should be ok to generate in at low power.
Correct me if I am wrong...but I should be ok to test it in the amp if all those perameters are met.
Current is limited and protected by a fuse...voltage is regulated and steady and brought up from lowest point. I will be generating low power while monitoring heat, voltage and current draw of the amp and bias.
This bias has been tested on the bench under load.
Unless I am missing something I should be ok to test with the current limited at 200ma and a fuse.
What am I missing?
