On Apr 20, 6:20*pm, Tim Wescott wrote:
David wrote:
Looking for Crystal Radio Receiver Circuits, that have a voltage
quadrupler to increase headphone volume without batteries or AC power.

If you are quadrupling the voltage at the headphones, then you are, of
necessity, dividing the impedance at the detector by a factor of 16.

You only have so much power available at the antenna; a detector
followed by an unpowered "voltage quadrupler" won't extract any more
power than any other equivalently-well-matched detector, and so won't
put any more power to the headphones.

If you really want to do this passively, and not rely on some near-by
strong station for power, then you need to optimize your circuit and
headphones for efficiency, and you need to get a _lot_ of wire into the air.

--

Tim Wescott
Wescott Design Serviceshttp://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details athttp://www.wescottdesign.com/actfes/actfes.html

Hey OM:

What you claim may be true, but if I use a pair of 2000 ohm headphones
and have 100 millivolts into those phones, I would developed a power
into those headphones of 5 microwatts. Now if the voltage goes up 4
times to 400 millivolts the power developed into the phones is 80
microwatts. So it don't matter what the detector impedance is. The
headphones don't care what the impedance is, in this case.

Now if the detector impedance was 10,000 ohms then you have a
problem.

So basically is it optimized for say Edison electric to run a 50 amp
main to my house when I only use a 100 watt light bulb? The source
impedance is a lot lower than my 100 watt light bulb.

Don't forget a good ground connection also.

73 OM

de N8ZU