This first DRSSTC of mine evolved from the ISSTC work I had been doing at the time. Talking with Jimmy Hynes, who built the first DRSSTC, I decided I would give it a try, though with some changes from his design. Jimmy`s DRSSTC used an oscillator to generate the high frequency signal that drives the coil (about 66khz for his coil, I believe). Sinc
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e I`m not a big fan of using VCOs to tune tesla coils, I would use feedback from the secondary coil itself, ensuring that my driver was always in tune. I would then have to tune the primary circuit to this operating frequency. My feedback design started out very simple, and is seen below: The first schematic was what I originally used for my DRSSTCs. The second schematic is just a standard H-bridge, nothing too special there. I eventually made an important change to this very basic controller. The change was the addition of a JK flip flop, which would synchronize the interrupter turn off to the feedback zero crossing. This is important because with out this, the interrupter can disable the gate drivers during an RF half-cycle, where current could be very high. DRSSTCs rely on soft-switching, due to the resonant load. We try to avoid hard switching the several hundreds of amps that may be flowing through the primary circuit, as this is very hard on the IGBTs. Anyway, the flip flop ensures that this should not happen. Below is the schematic (updated 3/17/05): I still use the same basic schematic for the H-bridge, except now I use a voltage doubler at 140VAC, using a pair of 22000uf 200VDC electrolytic capacitors. These capacitors are much larger than needed, but they are what I had on hand. Here is how I make my GDTs. I take some cat-5 networking cable, and wrap 10 turns of it around a ferrite core. I then parallel all of the...
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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