3N249

Due to market price fluctuations, if you need to purchase or consult the price. You can contact us or emial to us:   sales@allicdata.com

Diodes - Bridge Rectifiers

A bridge rectifier is a diode assemblage of four individual diodes which enables alternating current (AC) to direct current (DC) conversion. The 3N249 is an old IC containing four independent diodes. The device is useful for signaling and supervisory purposes, as it can protect or limit the voltage or current present, or galvanically isolate circuits. This construction also guarantees a very robust electrical contact that makes it a much better choice than a single diode.

Application Field

The main application field for the 3N249 is power protection. It can be of great aid in solar energy systems, to protect batteries and other energy integrity related issues. It is ideal for noise-free power supply regulation, when switched mode voltage regulators just don’t cut it. It can also be used to regulate DC motor speed and, when connected as a full wave rectifier, to connect AC to DC circuits.

Additionally, it also has applications as a current interruptor, as a noise filter, and in voltage stabilizers, being quite dependable and relatively inexpensive. Since it is an IC, it is also more resistant to short circuits than bridge rectifiers consisting of individual diodes.

Working Principle

The 3N249 consists of four diodes arranged in a rectangle, which is why it is referred to as a 4-diode bridge. These individual diodes have their cathode terminals connected by a diagonal line, and their anode terminals connected by lines. Both of these diagonals are connected, forming a four-point circuit where current flows from the upper terminal to the lower terminal.

For AC input, the resulting waveform is squared, meaning that the entire voltage wave passes through. This way, if the AC source is peak variable, the resulting output is the same. The diodes serve as check valves, preventing current flow on the opposite direction of the bridge itself. This can be used to block undesirable current flow. Each 180 degree section of the circuit takes turns passing its voltage to the output, creating a full-wave rectified current.

This device is robust, inexpensive and its size makes it ideal for applications requiring minimum board space. Furthermore its four rectifier diodes are already built in, taking away the hassle of soldering individual diodes.

The specific data is subject to PDF, and the above content is for reference