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THE BELL SYSTEM TECHNICAL JOURNAL, JULY 195-4 



SO that they will not fire during the required rectifier starting time in- 

 terval. 



4.3. Magnetic Amplifier Regulated Rectifiers 

 4.31. 2-Volt, 3- Ampere Regulated Rectifier 



The control of direct current at low voltage levels has been complicated 

 by the lack of inexpensive low voltage reference standards, and b}^ the 

 very poor efficiencies of most rectifiers at low voltage. The new semi- 

 conductor devices have made important contributions in this field. 

 Germanium diodes with their relatively low forward resistance seem 

 naturally suited for use at low voltages, and the high sensitivity of 

 junction transistors likewise makes them an almost ideal amplifier of 

 small dc potentials. 



Fig. 21 illustrates the use of junction diodes, junction transistors and 

 a magnetic amplifier combined to furnish a regulated 2-volt, 3-ampere 

 dc power supply. It will be noticed that the circuit of Fig. 21 is very 



GND 



Fig. 21 — Two-volt three-ampere magnetic amplifier regulated rectifier. 



