Amps
[Top] [All Lists]

[Amps] 2sc2879 idle collector current

To: <amps@contesting.com>
Subject: [Amps] 2sc2879 idle collector current
From: 2 at vc.net (2)
Date: Fri Feb 21 05:57:06 2003

>> >2 wrote:
>> >>
>> >> >When adjusting the bias for a 2sc2879 amp operating at 15v, what
>should the
>> >> >resting collector current be for reasonably linear operation?  I've
>seen
>> >> >values
>> >> >suggested that range from 100 to 200 ma per transistor.
>> >> >
>> >> I use 200 per.
>> >
>> >Hi Rich,
>> >
>> >Just to be 100% sure -- since most of these amps have boards with a pair
>of
>> >transistors -- do you mean 200 per TRANSISTOR or 200 per BOARD?
>> >
>> The mfg of the radio said 200 for a pair.  That was not clean enough, so
>> I went with 200mA ea.
>> cheers, Vic
>
>    What was the flange temperature?
>
The radio uses a temp comp bias circuit.

cheerz, Bill

>    Remember that unless you're using a temperature
>    compensating bias circuit the resting collector current
>    will rise as the heatsink, flange, and B-E junction(s)
>    increase in temperature.  In a nutshell, what is Class B
>    and a little dirty at room temperature can quickly become
>    Class AB and clean after the first QSO--especially with
>    15 volts on the collector(s).
>--
>-------------------------------------------------------------------
> -=[Bill Eitner]=-
>
>Link to A.M. Tutorial and rec.radio.cb FAQ:
>http://www.bigradios.com/kd6tas
>-------------------------------------------------------------------
>
>


-  R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K, 
www.vcnet.com/measures.  
end

<Prev in Thread] Current Thread [Next in Thread>