This compact design forms a remotely operated switch that receives its control signal via the mains voltage. The switch is operated using the mains remote transmitter` described elsewhere in this issue. With this transmitter, a switch should be connected between pins 1 and 2 of K1. Depending on the application, this must be either a press contact
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or a make contact. The idea of the mains remote switch` is that a relay is energized in order to connect the mains voltage on K1 through to K2. The receiver` (a somewhat exaggerated term for such a simple design) is formed by Tr1 and the tuned circuit L1/C4. The network C1/Tr1/C2 serves as a coupled circuit tuned to the frequency of 143 kHz generated by the transmitter. The selectivity is determined by L1/C4 and is primarily dependent on the standard suppression coil L1. Gain for operating the relay is provided by T1. The amplified signal is smoothed by C6 and provides the voltage necessary to cause T2 to conduct and energize the relay. The voltage divider formed by P1, R1 and R2 provides a bias voltage for T1 in order to increase the sensitivity of the receiver. This also allows the relay to be energized without a received signal. D1ensures that C5 does not become charged and prevents T1 from conducting even more. The operation of the circuit is based on the fact that the incoming signal is sufficiently strong to overcome the hysteresis of the relay. Once the signal is no longer present, the relay must naturally again release. To be honest, it must be noted that the simple design of this circuit has the disadvantage that its sensitivity may be somewhat inadequate, depending on household circumstances. One possible solution is to reduce the frequency of the transmitter to the region between 95 and 125 kHz. The values of C1,...
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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