[time-nuts] HP 10811 update

paul swed paulswedb at gmail.com
Wed Jul 24 19:56:58 UTC 2013


Thanks Charles. I suspect all said the regulated output delivers 1 ma. It
doesn't feed much.
I have the 2n3904s so cheap test to see if that picks up the 45 Hz


On Wed, Jul 24, 2013 at 3:20 PM, Charles P. Steinmetz <
charles_steinmetz at lavabit.com> wrote:

> Paul wrote:
>
>  Q4 a 2n6429. What interesting about this transistor is its beta at
>> 1 ma is 500 min and max is 1300. Its not a darlington.
>>
>
> A BC549C or BC550C should work fine, and they are readily available and
> cheap.  A 2N3904 should be fine, too, but the current regulator diode on
> the zener is only a 1mA part, so the 2N3904's increased base current will
> leave a wee bit less for the already-starved zener.  Shouldn't be a
> problem, though.  Noise of the transistor is not a factor (within reason)
> -- the zener will dominate that.
>
> Best regards,
>
> Charles
>
>
>
>
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