Browse Prior Art Database

Single Shot

IP.com Disclosure Number: IPCOM000095595D
Original Publication Date: 1964-Mar-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Chua, C: AUTHOR

Abstract

This single-shot has a pulse width ranging from zero to a maximum determined by the magnitude of relatively precise passive components. The single-shot recovery is directly proportional to the pulse width permitting the use of fixed duty cycles.

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Single Shot

This single-shot has a pulse width ranging from zero to a maximum determined by the magnitude of relatively precise passive components. The single-shot recovery is directly proportional to the pulse width permitting the use of fixed duty cycles.

Normally, transistor T1 is in saturation and transistor T2 is cut off. An input signal of appropriate polarity turns on T1 which conducts. Regenerative action occurs to turn off T2. T1 saturates when conducting. A negative voltage level appears between the base and ground of T2. The negative voltage level is substantially equal to >Vcc - Vce (saturated) R1|/(R1+R2), where Vcc equals the power supply voltage. Vce ( saturated) equals the voltage drop across T1. R1 equals the resistance of a portion of voltage divider 20. R2 equals the resistance of the remainder of divider 20. R1 plus R2 equals the total resistance of divider
20.

The negative voltage level across T2 rises toward Vcc at an exponential rate. This is determined substantially by the time constant of resistor R3 and capacitor
C. R2 does not play a significant part in the determination of the time constant, since resistor R3 is an order of magnitude larger than divider 20. When the base voltage across T2 reaches a threshold, conduction of T2 resumes. Regenerative action again occurs and the quiescent conditions are reestablished. The quiescent voltage condition at C is reestablished at an exponential rate determined by the time constant R1C. The rec...