There are systems in which it is imperative that the supply voltage of, say, a motor, always has the correct polarity. It is, of course, possible to use a bridge rectifier for this, but if large currents are involved, this is not always possible. This may be because large voltage drops across diodes result in appreciable heat dissipation, or that
Click here to download the full size of the above Circuit.
the peak current exceeds the current rating of a diode. Fortunately, a good, inexpensive mechanical rectifier may be constructed with the aid of a relay. In the diagram, the supply voltage is applied to K1, while the motor that needs a supply with correct polarity is linked to K2. Provided fuse F1 is intact, a positive potential at terminal a of K1 will be applied to the positive terminal of K2. Diode D2 prevents the relay being energized. When the polarity at K1 is reversed, the relay will be energized via D2. The relay contacts then interchange the connections to the terminals of K2 to ensure that the previous polarity of the supply to the load is retained. Diode D1 is a freewheeling diode for the relay coil. The type of relay to be used depends on the requisite operating voltage and the current through its contacts. Other parts of the circuit are not critical. It stands to reason that the circuit is not suitable for use with a small battery, since the relay coil draws a fairly large current.
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: