[Amps] Regulated AB Bias schematic

[G3rzp@aol.com]

In a message dated 10/03/2005 01:23:29 GMT Standard Time, craxd1 at ezwv.com  
writes:

What  they did for sensing the heat was use the base to emitter junction of a 
 transistor as a diode. They mount the tab of the transistor as close to the  
finals as possible onto the heatsink. As the heatsink gets hotter, the heat 
is  transfered into the diode junction thus changing its resistance. This 
changing  resistance then is used to control the regulator and control thermal  
runaway.



The original RCA circuit used a transistor with an extra diode actually on  
chip for the sensing. Never quite understood why that didn't become a more  
common practice.
 
73
 
Peter G3RZP