EMRFD Message Archive 12471

Message Date From Subject
12471 2016-03-04 18:34:58 Ken Chase Supply decouple resistor

Hi All

 

Looking through EMRFD, some of the small signal amp have a resistor in the supply line to toroid then collector. I think this is called decoupling resistor.

 

What is the purpose of this resistor?

 

Example in EMRFD Page 2.20 Fig 2.57 43 ohm on the 12 volt line.

 

73

 

Ken VA3ABN

12472 2016-03-04 19:32:26 Dana Myers Re: Supply decouple resistor
12473 2016-03-04 20:16:18 farhanbox@gmail.c... Re: Supply decouple resistor

if there is a resistor in series with an inductor as a load to the collector, it is a bias to limit the voltage on the collector. this is often used in mmics where we do not have control over the internal biasing. i guess there was an app note on some mmic vendor's site.

- f

12474 2016-03-04 20:20:27 Dana Myers Re: Supply decouple resistor
12475 2016-03-04 21:49:41 kerrypwr Re: Supply decouple resistor
The resistor provides de-coupling and also affects the bias; see the note relating to Fig 2.15 and Chapter 2.7.

Kerry VK2TIL.