Power Supplies

Author: Leonard Krugman

As the number of applications for transistors increase, many new power supply systems will be required to fit in efficiently with the particular design. The power requirements of an individual circuit is very small, so small in fact, that quite often the life expectancy of the bias battery is the same as its normal shelf life. Nevertheless, in some applications it may be desirable to derive the power supply from an existing a-c source. Figure 7-9 illustrates an experimental power supply, fabricated for a particular application, where a bias of 30 volts and a drain of 10 ma were required. The circuit is a basic full-wave rectifier terminated in an R-C filter. With the values shown, the ripple is less than one percent.

Fig. 7-9. Transistor power supply.