# Cockcroft - Walton voltage multiplier

The Cockcroft - Walton uses an ac current and its output is dc. In a YouTube video the creator has stated that he can get the same result using a dc single input source. He does mention some sort of magnetic resonator though. I’m lost as to how this actually works though. Does the resonator just provide a connection to ground and therefore alternates current flow instead of alternating current direction.
I’d like to try building something similar and all the videos I’ve seen show a ground connection so thought maybe a micro controller and switching between an open or closed circuit might be the same as creating frequency. Any advice welcome.

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I’m not sure opening and closing a circuit will work but alternating between connecting to positive and negative will work. You can use a half-bridge or motordriver chip controlled by a microcontroller.

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Here’s a simplified schematic:

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Hi Rodney,

While not a Cockroft Walton Multiplier this video on a Dickson multiplier shows that its possible: Let's build a voltage multiplier! - YouTube

PS: watch out for high voltages!

Liam

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Just to be sure I understand correctly a switch that connects the positive input straight to ground and switches back to power the circuit. Like short circuiting straight to ground momentarily

Looking at voltage potential between the atmosphere and ground. Voltage =100 volt per metre in height. If we built a voltage multiplier and a wire extended to a height of 10 metres we can access 1000 volts but there is only one input.

There are two switches and it’s important to turn one off before turning the other one on so you don’t get the circuit shorted from positive to ground at the same time.

Open and close sw1 then open and close sw2, and repeat.

It’s difficult to get a lot of power out of them starting from microcontroller voltages and dangerous starting with high voltages. With a 5V supply and voltage drops acros the diodes you might need around 250 stages to get to 1000V (Just a guess, didn’t calculate it) I’m tempted to try it out tomorrow, I’ll post the results if I do.

Hi Liam
Memories
This used to be a common circuit many years ago (read valve era) where high voltages needed to be generated. I think very early TVs used it to generate the EHT voltages for the CRT. The down side of this arrangement as demonstrated in the video is the high source impedance. In other words the current capability reduces with the number of multiplier stages and the load regulation decreases in proportion. Fortunately the EHT requirement for a CRT is only µA and not many of them.

Nevertheless voltage doublers were fairly common if the load was constant the current requirement could be designed in.

With all the low voltage stuff these days there is not much call for this type of thing but interesting just the same.
Cheers Bob

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Not looking to get 1000 volts out of the micro controller 5 volts. At 10 metres above ground there is a voltage potential of 1000 volts. The potential is volts = 100 volts per metre. If we create a pole that is 10 metres high with a conductor that leads to voltage multiplier circuit we can raise the voltage enough to drive an electrostatic motor. Companies are trying this with conductors at higher heights and feeding electrostatic motors. The confusing part for me is where they say the circuit works on ac input and yet they claim it still works on single wire input. Every schematic of the circuit has a ground connection in the first stage.

Looking at atmospheric electricity. Volts = 100 volt per metre in height above ground. A 10 metre pole with a conductor will conduct 1000 volts to ground. Companies are trying conductors at higher heights and using the voltage to drive electrostatic motors. A creator on YouTube claims the voltage multiplier circuit could be used with the single input from what is a dc current. Every circuit I see has a positive input and a ground connection and is based on an ac current driving it. With a positive and negative dc output. Wondering how an ac current can be achieved to drive the circuit. The creator did mention a magnetic resonator so trying to find how to emulate that resonance with a microcontroller

Hi Rodney
Just where did all that come from. You are saying that a 10M pole with a wire on it will pick up 1000V !!!.
The closest you will get with that is if you get a lightning strike and then you might get a lot more than you bargained for.

It is true that if you have a 10M pole with a wire acting as a radio frequency transmitting antenna you could get 1000V of RF at the top but you have to drive it with lots of watts at the bottom to do this.

You might have got a bit confused with the antenna situation.
A practical example. I once fitted a 35W AM HF transceiver to a vehicle which was headed out into the Simpson Desert. The antenna was a 3M whip fitted to the front bumper. This antenna had a 3mm diameter brass spike in the top to fine tune the antenna once in situ. When tuned there was enough voltage on the sharp spike to ionise the air and we could hear every word spoken into the microphone coming off the antenna spike. The solution was to solder a small brass sphere to the top of the spike to remove the sharp point. And that was only 35W. A broadcast antenna gets 5kW or more.
Cheers Bob

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There is not much amperage in it. Lots of things on YouTube where they use drones to get a conductor 100 metres into the air and receive a high voltage spark at ground level. Atmospheric electricity it’s basically electrostatic. Can’t drive a conventional electric motor with it but they build electrostatic motors and get rotation.

Video explains better. How Powering with Atmospheric Electricity Works - YouTube

Here is the chapter from Feynman:
https://www.feynmanlectures.caltech.edu/II_09.html

It’s pretty interesting, sticking a long wire into the sky would create a high voltage, ultra low current source. The Cockcroft-Walton generator needs low-voltage high current.

As an experiment, if you’re unable to get the wire high enough to get some corona discharge you could add a battery powered high-voltage source to the wire, like maybe, umm, a Cockcroft-Walton to ionise some air at the top of the wire then current will flow down the wire.

If you used the power stored in C5 you’d be using power from the atmosphere. But in this experiment you might be consuming more power than you generate, you’d need a more efficient way to ionise the air.

(Edit: current from the circuit might flow from V_out to earth ground charging the capacitor from the battery. Maybe a transformer based approach would isolate the circuit and ensure and current charging C5 comes from the atmosphere)

It’s an interesting concept. I think Russians in the early 1900s had an idea to place hundreds of balloons in the air with conductors and get free power. I’ll see if I can find the video I watched where the creator says he thinks he can use a voltage multiplier in the system.

Hi Robert,
I thought it was a bit crazy at first. But read what Feynman wrote about it. It makes sense. Actually getting any measurable power from the idea is a different story. In your example, the top of the pole is still at 0V because the field changes around the pole. Here is a schematic of the 10m example:

In theory, I’d be quite comfortable touching the output of the voltage divider.

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Hi Brendon

A similar system has been in use for many years (my personal knowledge 50) in coal mines and other places where a lightning strike could be disastrous.
A copper cable is connected to a spike (usually multiple points) as high as possible and a voltage applied which is ALMOST enough to ionise the air at the spikes. The idea is to discharge any cloud or air mass in the immediate vicinity in an attempt to prevent local lightning strikes. The idea is that when a cloud or air mass charges enough ionisation occurs and the charge will be removed before it can discharge via the air in the form of a lightning strike. This system appears to work and is used where high structures which would be attractive to such strikes exist in dangerous places

This is not to be confused with the lightning spikes and conductors on towers like TV antennas, broadcast antennas and other high structures where the purpose here is not to prevent strikes but conduct the high currents directly to ground. In a straight line I might add as lightning does not go around bends.
Cheers Bob

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In this video he uses a 9 volt dc current and switches using a 555 timer and then a mosfet. I had thought maybe a microcontroller driving a mosfet but not sure how the mosfet would operate using high voltage ( 1000 volt ) and micro amps. Let's build a voltage multiplier! - YouTube

That’s a good video. The problem is a starting voltage of 1000 volts so how do we create the switching. The 555 timer and mosfet work fine but I have no idea how they would handle 1000 volt and micro Amps of current.

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