TY - JOUR AU1 - Brach, E. J. AU2 - Wiggins, B. W. AB - Med. & biol. Engng. Vol. 5, pp. 613--614. Pergamon Press, 1967. Printed in Great Britain TECHNICAL NOTE THE USE of built-in rechargeable batteries for portable UJT is reverse-biased and therefore non-conducting. instruments has increased since the introduction of As capacitor C= is charged through R2, the emitter voltage inexpensive cells such as the NiCad. A common require- reaches the peak voltage (Vp), the emitter is then forward ment in portable bioinstrumentation is recharging the biased and the uYr switches on. C= then discharges batteries and a novel circuit is described for this purpose. through the primary of T2 producing a sharp pulse at the The circuit uses silicon controlled-rectifiers because (a) secondary which triggers the silicon controlled-rectifiers. they are et~cient rectifiers; (b) they are efficient static As the voltage across the emitter falls to a value less than power switches and (c) their power gain between input 2 V, due to the discharge of C=, the emitter ceases to and output is high, allowing the use of inexpensive low- conduct and the uyr turns off. This cycle is then power controt circuits. repeated with a periodic time (T): Features of the circuit are: (a) charging is performed at constant TI - Battery charger for portable instruments JF - Medical & Biological Engineering & Computing DO - 10.1007/bf02474256 DA - 1967-11-01 UR - https://www.deepdyve.com/lp/springer-journals/battery-charger-for-portable-instruments-0L1f0yCjjA SP - 613 EP - 614 VL - 5 IS - 6 DP - DeepDyve ER -