The prototype of Keypad Switch No. 2 was built using only the Stripboard Layout as a guide. So - if you have faithfully reproduced that layout - you will have a working circuit. Once you`re satisfied that your layout is correct - and you have made a careful and thorough check of the underside of the board - it`s time to power-up the circuit and tes
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t its operation. This is always an anxious moment. If you construct a lot of circuits - you might consider building the Current Limiting Power Supply - or alternatively - you could add the Simple Current Limiter to your existing PSU. Both will let you set an upper limit on the amount of current supplied to your circuit - and so protect it from any serious damage. A resistor and a couple of LEDs are all that`s needed to demonstrate that the relay contacts are switching properly - and you can simulate the keypad-switches using short lengths of wire. Connect five short lengths of wire to the "A B C D & E " terminals. Connect a longer piece of wire to the "Com" terminal. You`re going to touch the short wires with it - so it needs to be long enough to reach as far as "E". Strip a little of the insulation from the ends of all six wires. = Connect a 2k2 resistor between the "+" terminal and the "Pole" Terminal. Connect an LED from the "N/C" terminal to the negative line. Connect another LED from the "N/O" terminal to the negative line. I used two different colour LEDs in the diagram because - in what follows - I wanted to be able to distinguish between them. You can use whatever colours you have available. = Finally, connect the 12-volts DC to the input terminals. Pay particular attention to the polarity of the supply. Note that the positive connection goes to the top terminal. = Turn On The Power The relay should energize - 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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