Very often when building modules low power required the stabilized power supply at different voltage with simultaneous connection. For example, to check and adjust the frequency response of the channel selectors SC-M-24 and SC-D-24 source must provide: voltage settings - 0,5...27 V; the AGC voltage is 8 V; voltage - 12 V to turn on the ranges.
Check and adjustment of imported equipment requires a power source with other the voltage values. For these and other purposes offer a relatively simple power supply, assembled available parts.
The basis of the source is parametric stabilizer, fed by the rectified voltage (Fig. 1). The power transformer output transformer personnel scan black and white TV TCE-LM. Rectifier diodes, available, with a permissible reverse voltage of at least 50 V. Capacitors can be used any of an oxide, for example C50-35.
Before the establishment of the power source should be connected to the network via adjustable autotransformer and set the input voltage of 220 V. Then instead constant of the resistor R1 is necessary to include a variable resistance 1 kω. In open circuit (point a) connect a milliammeter and a variable resistor establish a current in the range of 10...15 mA. In the same way choose the resistance of the resistor R2. Milliammeter in this case connected in the gap the circuit at point B. the Variable resistors replace the constant with a close value resistance. Power resistors is determined by the product of the voltage drop the measured current.
If there is no Zener diode with the required voltage stabilization, it is obtained series connection of Zener diodes or the use of differential inclusions (Fig. 2). The total voltage in the first case is equal to the sum of the voltages each Zener diode, and the second difference.
When unstable mains voltage of the power source must be connected via stabilizer AC or adjustable autotransformer.
Such a power supply can also be collected using any stable source.
Author: N. Shatalov, p. Erba Krasnoyarsk region