[Amps] switchable zener cathode bias

[pc5m, Carel]

Hi Steve,

I suppose you use a low power zener and 2n3055: If you just connect via a
relay of single pole switch the lower valued zener in parallel with the
higher voltage zener all would be fine. 

Gl, Carel

> -----Original Message-----
> From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com] On
> Behalf Of Steve Flood
> Sent: Tuesday, December 30, 2008 5:53 PM
> To: amps at contesting.com; rfamplifiers at yahoogroups.com
> Subject: [Amps] switchable zener cathode bias
> 
> Considering the common zener bias circuit (with the 2n3055 and resistor),
> what precautions should be taken if I wanted two different zeners (and
> associated bias voltages) selected by a switch or relay?   Is there a
> danger in the moment when the switch/relay throw is transferrring from one
> pole to the other and neither zener is in the circuit?   Likewise, if I
> used a make-before-break setup, can the two zeners be in parallel for a
> moment without causing trouble?
> 
> Thanks,
> Steve KK7UV
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