Those of you who own large 500 watt and higher Astron linear power supplies, and even large HF amplifiers, know all too well that `GNNNNnng` sound that they often make when turned on. This is due to the high inrush (surge) current flowing into the transformer when the filter capacitor is discharged. Depending on the size of the supply, this surg
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e can exceed the rating of the circuit breaker on the outlet the supply is plugged into, but as it`s so brief, the fuse on the back of the supply rarely blows during these surges. There are several ways to prevent this: Leave the supply on all the time. Even if it`s left on all the time, there will still be momentary power outages and interruptions, so this really isn`t a true solution. Purchase a commercial inrush current limiting device for about $80US. Here`s one that plugs into the wall, has its own on/off switch, and provides an inrush current limited outlet for any load. Unfortunately you must use the power switch in the external box and leave the supply`s conveniently located power switch turned on all the time. You can make a similar device yourself with a relay and a resistor and you can install it between the power switch and the transformer inside your unit. Add a thermistor in series with the input of the supply. This is a small negative temperature coefficient device that gets wired in series with the transformer. It has a high initial resistance (high compared to the resistance the transformer presents when power is first applied) but as current is drawn and the device gets hot, the resistance decreases (hence the negative temperature coefficient). It regulates itself, providing a current limiting resistance when cold and almost no resistance when hot. It does this with no moving parts, unlike units that use a...
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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