The right capacitor for a voltage multiplier

Thread Starter

Drmario5237

Joined Oct 14, 2018
65
Hello I was wonder how I am to choose the right mearsuement of capsity and voltage rating for a voltage multiplier circuit when I'm basing what voltage and amps I'm getting from a antenna and tank circuit hooked to the multiplier. In this case I'm having trouble figuring out the voltage and amps from the frilis transmission formula because the received power is in watts or deibles which tells me nothing of the actual amps or voltage then not knowing how to choose the right capsity for the voltage multiplier even if I knew the inputs confuses me even more. Thanks.
 

Alec_t

Joined Sep 17, 2013
11,540
Post a schematic, with component identifiers, and perhaps we can make suggestions.
If the multiplier is a conventional Cockroft-Walton type I wouldn't have thought that was appropriate to use with an 'antenna and tank circuit hooked to the multiplier'.
 

crutschow

Joined Mar 14, 2008
25,269
This is a nit, but I've seen the word capsitor used for capacitor a number of times.
Is that from some language other than English?
 

Thread Starter

Drmario5237

Joined Oct 14, 2018
65
Post a schematic, with component identifiers, and perhaps we can make suggestions.
If the multiplier is a conventional Cockroft-Walton type I wouldn't have thought that was appropriate to use with an 'antenna and tank circuit hooked to the multiplier'.
wirelesssept14th2019.png
 

Thread Starter

Drmario5237

Joined Oct 14, 2018
65
The rest of the schematic (outside the tank circuit and voltage multiplier) is for storing the current from the rest of the system in two sets of capasitorscontroled charging and discharging by transistors which lead to zenner diodes for voltage ragulation and to a constant current diode for control of current. I hoping to get 500 milliamps out of the sysytem at 5 volts. its according to the charging of the capasitors and how many cycles it of frequincy it will take to charge them and according to how much i get from the antenna and tank circuit. Id like to use a 7 watt transmitter if possible at no further than a 100 feet and around 1650 kilohertz. any recomdation of transmitter wattage, distance and hertz
 

MisterBill2

Joined Jan 23, 2018
6,758
OK, now with actual numbers and a description it becomes possible to provide a meaningful response that is better than a guess. 5 volts at 500 milliamps is 2 1/2 watts of power. That is quite a lot of power to capture from a radiated signal. A voltage multiplier could increase the voltage but the limitation is that power is a voltage times current product and so the multiplier does not increase power. That is a fundamental relationship that is inescapable.
Transmitting power in a specific direction has been researched for many decades for communications purposes, and there are a lot of designs for directional antennas. At 1650 kC they are not small antennas at all.
There has also been a large effort on wireless battery charging, which usually leads to hard to believe claims as to efficiency, even at very close distances.
If the entire circuit were 100% efficient then you would need to capture those 2.5 watts of power from a 7 watt transmitter at up to 100 feet. If the antenna at the transmitter could focus all of the power into a very narrow beam it is still unlikely that you could capture about a third of the radiated power.
There may be some other way that your goal could be achieved, but this is not it.
 

Alec_t

Joined Sep 17, 2013
11,540
In your country is a licence required to transmit on 1650kHz? Your transmission falls in the medium wave radio broadcast band.
 

MisterBill2

Joined Jan 23, 2018
6,758
A few years ago a friend of mine, Mister Herf, had constructed a horn antenna to direct the energy from a magnetron tube originally intended for a microwave oven. That assembly was able to direct a fairly narrow beam, but even with 800 watts it did not produce much voltage at 50 feet to be picked up by a small antenna. With transmissions above a small power level there usually are licensing requirements, I was only addressing the technical aspects in my prior posting.
If your goal is simply remote control there are many devices available that work on a number of different frequencies.
So an additional description of the purpose and intent of the project will allow more useful responses.
 

Thread Starter

Drmario5237

Joined Oct 14, 2018
65
I had an idea of using am transmission at a certain frequincyfor the carrier wave and a frequicy half the carrier wave for a side band with a higher amplitude than the carrier wave so that the tank circuit resonantes more so more power is gotten from the radio wave kinda of like harmonic resoanance.sideband5.png sideband10.png
 

MisterBill2

Joined Jan 23, 2018
6,758
No matter what the modulation and resultant carrier are, all of that power must be delivered by the transmitter. So while transmitted power can indeed be increased by modulation, that power is not free. Modulation in an AM system requires additional power.
 
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