[Amps] yeah - it works !!

Dan Sawyer dansawyer at earthlink.net
Sat May 1 21:42:28 EDT 2004


All,

I recently posted "proud owner of a ... MRF154 amp" and got back a lot 
of helpful replies. Well I brought up the gate voltage first. The 
current draw was very low and there was no bias across the gate. I 
measured the 'gate' circuit, it was producing +5 volts. This would be 
consistent with a control line so I put a 100 ohm resister across it. 
The result was about 3 volts bias on the gate - so far so good.

Now we at the edge - I added about 26 volts to the drain and nothing 
seemed to happen. So it was time to connect everything up. It all 
worked. The frequency response was best at about 2 MHz and fell of 
slowly up to about 30 MHz.

The only anomaly is the gain seems to be dependent on the voltage 
applied to gate bias. The peak is with about 12.5 Volts in. Output drops

Here are a few questions:

1. From here is most likely safe to move the drain supply to 50V??

2. The gate control circuit seems to turn on with 100 ohms or less. 
Would a short reasonably burn up the control circuit??

3. I tried to look at the drain to see the output with a high impedance 
scope. No signal was visible. This is confusing.

Thanks,
Dan





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