As a power source for certain circuits on operational amplifiers, low power sources of a few volts (12-15) are more often used. To date, the most widely used voltage regulator is 12 volts, made using three-output integrated units. Their purpose is to obtain at the output of various voltages and electric currents. The main components are integrated circuits of domestic production KR142EN8B and their imported analogues of the MS78xx and MS79xx series or simply 78xx and 79xx.
Domestic and foreign types of stabilizers
The Russian integrated unit KR142EN8B (abbreviated name KREN8B) provides a normal output voltage of twelve volts.
Imported stabilizers of the above series have the following designations: the initial even number (78) showspurpose - positive output current, odd number (79) - negative output voltage. The last two digits (12 or 05) indicate the magnitude of the output electric current. For example: 7912 - microcircuit - voltage regulator 12V with negative polarity, 7805 - microcircuit - a similar unit, only 5 volts and with positive polarity.
Three-pin stabilizer, as its name suggests, has three pins that provide connection to an external electrical circuit: input, output and common. A common terminal is used to connect to the power supply housing ("ground"). The input and common pins are used to supply the input voltage, and the working output is obtained at the "output" and "common" pins.
A 12 volt voltage regulator will work normally if the input current at maximum load exceeds the output by at least 2.5 volts. In this case, the value of the maximum input source should not exceed thirty volts. In addition, keep in mind that an increased input voltage gives an increase in power, while the 12V stabilizer starts to heat up. Accordingly, to prevent damage, it is necessary to use a heat sink.
A standard power supply is assembled from an electrolytic capacitor with a capacity of up to 10,000 microfarads, a full-wave bridge rectifier from diodes with a reverse voltage of 50 volts and a forward current of 3 A, a fuse (0.5 A). 12 volt voltage stabilizer– 7912 or 7812 (KREN8B).
Using a similar unit for the operation of the assembled device, it is required to arrange 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 that use a 12-volt voltage stabilizer in their composition allow their use for powering various types of devices and units made using TTL integrated logic circuits, including devices for automotive equipment.
