With the advent of commercially inexpensive and reliable three-terminal integrated voltage stabilizers, it is possible to build a simple power supply to a number of the most often applied voltages (Fig. 2.26).
The power supply consists of a step-down transformer 220 V / 30 V, bridge rectifier on the basis of the module and CCA three stabilizers series HH (KEN) 5 V, 9 V and 12 V. On the front panel removed the switch SA2 and the display unit on the seven-segment displays. Series integral stabilizers HH provides an output load current up to 1 A, equipped with internal protection for cases of overheating or excessive load current by reducing the output current. A series of integrated stabilizers HH designed for negative voltages. The voltage stabilization is indicated in the last two digits designate the chips.
Compliance stabilizers series HH and HH domestic series CR and CR reflected in the table. 2.1.
Table 2.1
A few comments on the application. The input voltage must not exceed 30...35 V. the voltage Difference when connecting the stabilizers step shall 2 V. To smooth the ripple should be applied at the input electrolytic capacitor with a minimum capacity of 4700 μf, and the output supply high frequency ceramic capacity of at least 0.47 µf.
To obtain a bipolar voltage, it is possible to combine stabilizers series HH and HH (Fig. 2.27).
The diodes connected to the output, protect the unit from incorrect inclusion.
Author: A. P. Seman