SELECTION GALLERY (PART 3)

Previous: Selection gallery - Part 2 (Flyback transformer based electrical phenomena)

Cockcroft-Walton multiplier based electrical phenomena

A Cockcroft-Walton generator/multiplier/cascade uses capacitors and diodes to multiply the input voltage (AC to DC). When using high-voltage components, the input voltage itself can also be relatively high. This article features a selection of photos and videos without much explanation or technical information about the electrical phenomena displayed.

Preview images can (usually) be clicked on for larger versions of the image.

Unipolar version i.e. 6 stage with maximum input 10kV AC peak

Some preliminary photos from a sacrificial prototype circuit which was damaged shortly after from pushing it. I only managed to capture a few photos before it was damaged. The sparks from this prototype were about 10cm or 4 inches long but louder and brighter than those observed from the ignition coil configuration:

The corona discharge produced by this circuit when the electrodes were about 12cm apart was far more impressive than anything I have previously observed with ignition coils and flyback transformers (much more visually and audibly obvious):

Bipolar version i.e. 2 x 4 stage with maximum input 30kV AC peak

This was designed for a maximum of 50-60cm sparks and aiming for at least 30-50cm sparks in practice. The absolute ideal theoretical maximum is 30kV (peak) AC input and 480kV DC output, but it would be significantly lower in practice. After initially disappointing results due to an inadequate input, better performance was achieved with a new driver.

Here we start with a spark gap of about 20cm or 8 inches (120kV); although the photos below were taken with different settings and ambient light levels, the brighter or thicker sparks were more impressive than the ignition coil sparks:

A (close up) example of a localized streamer which appears to connect back to the main spark:

A (blurry) night-time video of 20cm sparks, with about 90cm distance from the camera in 5x zoom:

If the above video is not functioning or you want to download the file manually for viewing later:
[medium resolution and/or medium quality] : S100-M6102-800x450mq.mp4 (623KB)

During the next session, sparks of 32cm or 12.5 inches (approximately 180kV) were achieved. A 30cm ruler and an artist LEGO man figurine stuck on black board were included in the setup to get a better sense of scale:

Below is a prolonged exposure shot of sparks at approximately 38cm or 15 inches (215kV):

Below is a regular exposure shot of sparks at approximately 42cm or 16.5 inches (235kV):

Below is a short video of the same setup as the above photo:

If the above video is not functioning or you want to download the file manually for viewing later:
[higher resolution and/or higher quality] : S100-M6157-1280x720hq.mp4 (4.45MB)
[medium resolution and/or medium quality] : S100-M6157-800x450mq.mp4 (857KB)

Some corona discharge from a failed attempt to get 45cm (17.7 inches) or 250kV.

A 50cm spark gap (nearly 20 inches, requiring 275kV) was achieved once, but the driver circuit was damaged from pushing it too hard without adequate current overload protection, and the single spark observed was not captured on camera. Once the driver was fixed, the Cockcroft-Walton generator worked again. Currently planning to acquire a better driver.

A few months later (but before the new driver was completed) another run achieved up to 45cm / 17.7 inches / 250kV:

Below is a short video of the same setup as the above photo:

If the above video is not functioning or you want to download the file manually for viewing later:
[medium resolution and/or medium quality] : S100-M6242-800x450mq.mp4 (732KB)

Same setup on a different day with a little more background light remaining in the evening:

It may not be fully visible in this photo but when a black air-cored plastic backing was behind the towers, corona discharge also appeared out of the edge of the plastic (see upper middle part of the following image):

At a later date someone came over with their camera and this was quickly captured from the other side:

I still want to see if I can achieve 50 to 60cm out of these towers, but work on the driver has been delayed by health related limitations and also other commitments or responsibilities which have taken priority.

Next: Selection gallery - Part 4 (Marx impulse generator based electrical phenomena)

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