Zener-Diode-Regulated Direct-Current Power Supplies
J. Cleary · American Journal of Physics · 1965
Direct-current power supplies with Zener-diode-output voltage regulation are considered in relation to their protection against short-circuiting of their output terminals. It is shown that increasing the input voltage and the series resistance for a given output voltage reduces the ratio of the short-circuit current to the normal load current, allowing the design of power supplies which will sustain prolonged shorting of their output terminals. Criteria for the optimum circuit values for protection are considered. Universal curves of the powers and currents in each part of the circuit are given as functions of the ratio of input to output voltage. The results are generally applicable to Zener diode and glow-discharge-regulator power supplies. The treatment is presented in some detail to emphasize the value of mathematical analysis of apparently simple problems. Brief results are given of measurements on a power supply employing the principles outlined.