How to apply a voltage regulator of 12 volts

As a power source of certain circuits onOperational amplifiers often use low power sources of several volts (12-15). To date, the most widely used voltage stabilizer 12 volts, performed using three-lead integrated units. Their purpose is to obtain at the output a different voltage and an electric current. The main components are integrated microcircuits of domestic production KR142EN8B and their import analogues of the series MC78xx and MS79xx or simply 78xx and 79xx.

The Russian integrated unit KR142EN8B (abbreviated name KREN8B) provides a normal output voltage of twelve volts.

Import stabilizers of the above series havethe following notation: the initial even number (78) shows the destination - positive output current, odd number (79) - negative output voltage. The last two digits (12 or 05) indicate the magnitude of the output current strength. For example: 7912 - microcircuit - voltage regulator 12V with negative polarity, 7805 - chip - similar unit, only 5 volts and with positive polarity.

A three-output stabilizer, as evidencedits name, has three outputs that provide connection to an external electrical circuit: input, output and common. A common output is used to connect to the power supply housing (ground). The input and common terminals are used to supply the input voltage, and the working output is obtained at the outputs "output" and "common."

Voltage stabilizer 12 volts will be normalwork in the event that the input current at the maximum permissible load exceeds the output by at least 2.5 volts. In this case, the maximum input source should not exceed thirty volts. In addition, take into account that the increased input voltage gives a power gain, the 12V stabilizer starts to heat up at the same time. Accordingly, to prevent breakage, it is necessary to use a heat sink.

A standard power supply is assembled froman electrolytic capacitor with a capacity of up to 10,000 μF, a full-wave bridge rectifier from diodes having a reverse voltage of 50 volts and a forward current of 3 A, a fuse (0.5 A). The voltage regulator itself is 12 volts - 7912 or 7812 (KREN8B).

Using the collected device to worksuch an assembly, it is required to locate the electronic components in such a way that the length between the mounting connections is the smallest, and the removal of the radiator is the largest. For cooling, it is best to take standard finned radiators with sufficient surface area, or metal plates.

Sources used in its compositionvoltage stabilizer 12 volts, they allow their use for power supplies of various types of devices and units, performed with the use of TTL integral logic circuits, including devices for automotive equipment.