On 14-Mar-12 17:35, RussellMc wrote:
>> I tried to simulate this in LTSpice over lunch;
>
> Lonnnnng lunch :-)
>
>> nothing I have tried so far will make the circuit oscillate reliably in =
its original form, including make the capacitors significantly different va=
lues, adding some leakage, changing the collector resistors etc.  I get som=
e chaotic behaviour at power on, but not really what you'd expect from an L=
ED flasher.  Moving the base resistors up the Vcc immediately creates a per=
fectly operating astable.
>
>> That's obviously not to say it couldn't work in practice, but I very muc=
h doubt it will be reliable or repeatable between different builds.  I wond=
er how many people have thrown their soldering irons away in disgust after =
wasting hours with this?
>
> The sample of one user that I am aware of who has built it says it
> works well. Much to my chagrin :-).
>
>
>      Russell
>

It works in LTSpice too. It is a bad design but it does work.

Djula
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