[time-nuts] Zeeman Audio Source?
Chuck Harris
cfharris at erols.com
Thu Jan 13 02:30:27 UTC 2005
Hi Brooke,
OOPS! I missed the open circuit part. My 204C/D manual confirms that
you are absolutely right, you only have 10mW, and 2.5V, to work with.
So, I guess it's emitter follower time.
-Chuck
Brooke Clarke wrote:
> Hi Chusk:
>
> Maybe I'm having a bad hair day.
>
> Let's say we have a 4:1 step down transformer.
> The 204B puts out 5 Volts open circuit.
>
> When the transformer is installed between the 204B and the 50 Ohm Zeeman
> input we have:
>
> Voltage at transformer secondary = 5 / 4 = 1.25
> Source resistance of transformer secondary = 600 / (4*4) = 37.5 Ohms
>
> The new voltage divider at the secondary is 37.5 Ohms over 50 Ohms or 50
> /(37.5 + 50) = .571
> Output voltage is 0.771 * 1.25 = 0.714 Volts.
>
> Another way to look at it is if a 600 Ohm load is added and if the
> internal impedance is 600 Ohms then the voltage will drip to 2.5.
> power in the load = 2.5 * 2.5 / 600 = 10.4 mw vs the 20 mw needed for
> the Zeeman input.
>
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