Mosfet IRFP240/9240

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
sorry my typo.

What is the voltage gain of the amplifier at each of the test frequencies?

input 300mVpp and output ~10000mVpp measure both voltages using the same instrument. Divide output voltage by input voltage, (lets say you got 10100mVpp & 295mVpp).
The gain is 34.237times = 30.7dB at that test frequency.

Now plot gain vs frequency.
 
hi!
gud day...
i also did this kind of amplifier on breadboard, but i goto some problems encountered, what should i do if my R15 and R14 get too much heat, i already change it to a 10W 50 ohms??thank you

Just adjust bias. And stick to your 0,33 ohms!
When I was adjusting my bias I had the same problem.

Anyway, the problem with the bandwith is solved guys. Capacitor C2 is way to high!
 
that LED, it's used for thermal stability.
But how does it do this?

Any diode will decrease voltage across when warmed up.
LED = light emitting diode
The trick here is to place the diodes very close to heatsink. To feel the warmth.

When voltage goes down, then the current through output will be lower.
And the diodes will not decrease voltage.

When heatsink gets cold the voltage across diodes will go up
to give more current.

This stabilize the heat, the current in output stage.
Diodes will counteract the temperature of heatsink.
 
My the present menu

HQQF-55-506W-4-2.jpg
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.