[time-nuts] Zeeman Audio Source?

Chuck Harris cfharris at erols.com
Wed Jan 12 21:30:27 EST 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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