A relay is an electro-mechanical switch that opens and closes under the control of another electric circuit. When current flows through the coil of the relay, a magetic field is created that causes an armature to move, either making or breaking an electrical connection. When current is removed from the relay coil, the armature returns to its rest
Click here to download the full size of the above Circuit.
position. It is important to place a diode across the coil of the relay because a spike of voltage is generated when the current is removed from the coil due to the collapse of the magnetic field. This voltage spike can damage the sensitive electronic components controlling the circuit. The relay we are using in this example has a coil voltage of 5VDC, meaning the relay switch will be activated when 5VDC is supplied across the relay coil. The output pin of an Arduino does supply 5VDC, but the current that the relay requires to activate its switch is greater than the Arduino can safely supply. In this case, a 2N3904 transistor is used to supply a higher current 5VDC source to the relay coil (see multiple LEDs tutorial for more information on this circuit). The primary reason to use a relay is to switch a circuit of higher current than the Arduino is able to directly handle. A relay switch is much slower than a transistor, but has advantages in certain situations. When using a transistor to switch a higher current and/or voltage circuit, both the controller and switched currents need to share a common ground. There are times when this is not an option (such as switching an AC current circuit with a DC control circuit) and using a relay can be an option because it provides a mechanical separation between the circuits. Like standard manually operated manual switches, relays come with many different arrangements of switch poles...
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.....
characters left: