GB566102A - Improvements in electrical frequency-dividing and counting circuits - Google Patents

Abstract

566,102. Counting or dividing impulses. CALVERT, R., GOURIET, G. G., and. DAVIES, E. June 23, 1943, No. 10159. [Class 40 (v)] A frequencydividing or counting circuit comprises a discharge device with two control electrodes. One of the control electrodes is normally biassed to cut-off, the input signal applied thereto serving to raise the bias above cut-off ; the second electrode is associated with the condenser which is charged to bias the valve below cut-off consequent on receipt of impulses and discharged through a resistance. The time constant of the resistance condenser combination is such that the valve is held non- conductive for a multiple of the time period of the input signal. Fig. 1 shows a circuit in which positive impulses discharge condenser C3 and leave valve V1 blocked until C3 has recharged over resistance R4. The output of the valve V1 is applied, over a delay network so that the blocking of V1 is deferred until the pulse is completed, to an amplifier V3 to provide the output and render the normally blocked valve V2 conductive to discharge C3. Fig. 3 shows an arrangement in which a positive impulse is applied to the input of the valve V1 and on the cessation of the current on the removal of the pulse the valve V2 is rendered conductive to discharge condenser C3. As shown, the valve V1 is neutralized by a condenser C9 and the valve V2 is arranged as a cathode-follower to obtain a more satisfactory output characteristic. In a modification, a transformer in the output of a single valve supplies a pulse to charge a condenser which blocks the valve, the necessary time lag is provided by a shunt resistance to the condenser and by a resistance condenser combination in the cathode lead, Fig. 4 (not shown).