Will this circuit oscillate ?

[phil]

Hello all,

I need to know if the following circuit will/can oscillate,

http://www.geocities.com/myelectronicsrevision/fmtxastable.jpg

thanks!

 

[Watson A.Name - \"Watt Su]

"phil" <aaa@aaaaaaaa.com> wrote in message
news:c69md0$eg8$1@news.epidc.co.kr...

Hello all,

I need to know if the following circuit will/can oscillate,

http://www.geocities.com/myelectronicsrevision/fmtxastable.jpg

thanks!

As long as R1 and R3 are open or infinite resistance it will.
Otherwise, it might.

 

[Kevin Kilzer]

On Wed, 28 Apr 2004 17:20:23 -0700, "Watson A.Name - \"Watt Sun, the
Dark Remover\"" <NOSPAM@dslextreme.com> wrote:

"phil" <aaa@aaaaaaaa.com> wrote in message
news:c69md0$eg8$1@news.epidc.co.kr...
Hello all,

I need to know if the following circuit will/can oscillate,
http://www.geocities.com/myelectronicsrevision/fmtxastable.jpg

As long as R1 and R3 are open or infinite resistance it will.
Otherwise, it might.

Although I agree in principle, you probably need to have a finite R1
and R3 to help keep the frequency stable over temperature. Getting it
right will be the problem.

While we are at that node, though, there is the distinct possiblity
that the base-emitter junctions could be reverse biased with every
cycle. Many transistors have a low b-e breakdown voltage, and
reversing that junction can blow it out. Adding a reversed diode from
base to emitter usually fixes that problem, but costs you the extra
parts.

Kevin

 

[phil]

Now, can we move to a similar configuration
http://www.geocities.com/myelectronicsrevision/fmcct1.jpg

We can just pretend that the resistance of the push pull coil
plus the capacitor in parallel to it at the frequency of oscillation
will be our collector resistors from the previous configuration,
would that be a correct approach?