This unit is designed to power electronic calculators electronics BZ-18" or "electronics BZ-26" from the mains. In most cases calculators long been obsolete or defective, while the block BP-3, having a large "margin of safety", is functional and can be used to power consumer electronic devices.
The diagram of the power supply shown in the figure.
To the winding II of the mains transformer T1 connected full-wave rectifier, made in a bridge circuit to the diodes VD1-VD4. The rectified voltage is supplied to the stabilizer of two transistors providing an output voltage 5 V (nest+" and "P" connector X1) at rated current of 0.2 A. the power supply has a special socket with three the sockets for connecting the calculator.
The failure of the power supply unit are mainly associated with the failure of the filter capacitor C1, it is easy to determine the value of the voltage on it: if it is in the mode idling In less than 14, the capacitor should be replaced by "fresh".
To provide power to any other equipment operating voltage from 5 In, enough to replace the special socket SSS-44-SP corresponding connector. Stabilized output voltage within a certain range can be adjusted the replacement of the reference Zener diode VD5 other, with the corresponding voltage stabilization. So, the installation of Zener TV turns BP-3 in the current source with an output voltage of 9 V at load current of 0.1 A.
Output voltage 3 V, required to power the music player, it is easy to provide, using a Zener diode CSA. At the end of the power cord solder a plug that matches the connector on the player, cable wire connected to terminals "P" and "+" of the power supply. The switch SA1 for this mode should to be in position "P" (work).
When charging the battery, put the switch in position "Z" (charge). To ensure that nests on the "3" and "+" voltage 9 V, between them include Zener DB (anode to the nest "Z"), which together with resistor R3 (he now there should be a resistance of 300 Ohms and 1 watt) forms parametric voltage with a voltage of 9 V At a load current of 30 mA. In a result, the power supply can ensure operation of the equipment, which was previously fed from battery type "Corundum".
In this embodiment, at the end of the cable install the terminal block connector from coming in useless battery. Wire cable is connected, of course, with nests "W" and "+".
Now from the power supply unit can draw power from either one load or another or both, if you connect to the connector X1 corresponding reciprocal fork.
Author: A. Nizovtsev, Moscow