Consumer Electronics

POWER SUPPLY CIRCUITS FOR STEREO AMPLIFIERS

(1) Dual Supply: Fig. 21.16 is a schematic diagram for a simple split supply. The use of 1 Ω resistors on the filters keeps charging surges at a tolerable level to minimise the ripple content on the output.

 

 

Fig. 21.16 Dual supply circuit for the stereo preamplifier (notice the polarities of the electrolytics and zener diodes)

 

Since each of the 220 Ω series resistors has to drop about 6 volts, it establishes a zener current of about 25 mA. The load current and zener current are additive through each source resistor, bringing each resistor's dissipation close to one-half watt. To be conservative, ...