A basic mains driven Cockroft ladder high voltage generator is shown in the schematic. This is functionally the same as a project in Electronics Today International many years ago. The peak mains voltage of 340V appears across each capacitor and this is negative with respect to mains neutral and the surrounding environment. The orientation of the diodes defines the polarity. As the capacitors are in series, the voltages sum and at the top of the ladder about 7kV is present. A high value resistor is used at the output end to current limit the output. It is important to use a high voltage rated resistor or a string of lower voltage ones in series, so that the resistors maintain their stated resistance value. This design is for 220 to 240V mains power and a double length ladder would be needed for 110V supply.
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If a single dressmaking pin or other sharp point is connected to the EHT output you will be able to feel a slight breeze of negatively charged air molecules coming from the end of the point. The high charge density at the sharp point causes this ionisation and the negative ions are then repelled from the negatively charged pin, causing this ion breeze. You can also hear the point emitting a slight hiss and in very dark conditions you can just see the point glow slightly. The ionisation at the point tends to physically degrade it over time and this reduces the ionisation occurng there. Some commercially available air ionisers have precision shaped points of special alloys to counter this. One fun way to make sure that your ioniser is still ionising is to use the ion breeze thrust from the needles to spin a rotating emitter pair. A12cm long piece of stout copper wire is soldered into a 4mm plug and this is plugged into the EHT output. The top end of the wire has an ordinary steel dressmaking pin soldered to it. This is the point on which the spinning emitter arrangement balances. A section of aluminium foil about 20 cm long and 6cm wide is folded multiple times down its length until it is about 20cm long and 0.5cm wide. This gives the foil more strength. Try not to leave any sharp edges or points as these may ionise the air in unwanted places on the structure. If you can find a thick aluminium foil pie-tin then this is...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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