Anyone who frequently builds, repairs and tests equipment powered by mains voltage, will certainly have met with an unpleasant surprise when the plug inserted into the socket (or later) - loud explosion, destruction of equipment, flying pieces of components, circuit breakers tripped, darkness in the whole house and smoked plug :). Th
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ese surprises can be prevented using described test wall socket which serves to limit the maximum current, prevents tripping the breakers reduces the amount of destruction of the tested device. Especially useful for testing switching power supplies. The main part of the device are light bulbs, which in case of short circuit in the tested device limits the current. Incadescent bulbs can be used as power resistors, but the advantage bulbs is better availability compared with resistors, with a loss of hundreds of Watts. Another advantage of the bulbs is less resistance in cold state, so they behave as a variator or PTC, and until the fault current, voltage drop on them is just a little. I chose halogen 230V 300W and 500W. With the switches S1 and S2 can I thus choose three combinations: 300W, 500W and 800W (both lamps in parallel). Power input of tested equipment must always be much smaller than the rated power of light bulbs used to prevent significant voltage drop. I built the device into the metal case from the ATX PC supply (with two fans). Power entry is solved with the original cable connector, the output is classical socket located instead of one of the fans. The second fan is left to cool the bulbs. This fan is powered by a miniature transformer Tr1 and rectifier. How to use the device is very simple: connect the input to the mains and tested device to the output socket. Attention! The device operates at mains voltage,...
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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