The 220-240V AC mains source is stepped down to 9V AC by transformer X1. The transformer output is rectified by diodes D1 through D4 connected in bridge configuration and the positive DC source is straightly wired to the charger`s output contact, while the negative terminal is connected through current limiting resistor R2. LED2 operates as being
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a power indicator with resistor R1 serving as the current limiter and LED3 signifies the charging status. While in the charging period, about 3 volts drop happens across resistor R2, which switches on LED3 through resistor R3. The following diagram is a simple mobile phone battery charger circuit. The design is simple, easy to build and inexpensive. It use LM78xx regulator to make regulated and stable output voltage. Mobile phone chargers offered in the marketplace are quite expensive. The circuit shown right here shows up as a low-cost option to charge cell. This battery charger circuit is regulated and adjustable to make this circuit able to charge the mosto NiCAD battery. This circuit will work for single cell or multi battery cell which connected with series/parallel connection. The maximum voltage of the batteries should be 18V maximum. Power transistors Q1 and Q2 are connected as series regulators. Here the circuit diagram of simple and easy made battery level indicator. In general, in mobile phones, the battery levels is displayed in dot or bar style. This helps you to effortlessly acknowledge the battery level. On this page we provide a circuit that helps you to recognize the battery level of a instrument from. This is the cell phone shield circuit which can be used as mobile charger. Give protection to your cell phone from unexpected use or theft working with this easy circuit. It is able to produce a loud chirping...
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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