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Browse Prior Art Database

Function Generator

IP.com Disclosure Number: IPCOM000098294D
Original Publication Date: 1960-Jul-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Owen, FD: AUTHOR

Abstract

This circuit provides a parabolic voltage wave form E repetitively across a charging capacitor 10. This voltage is produced by periodically charging the capacitor with current through a summing transistor 11 and then discharging it through a transistor switch 12.

This text was extracted from a PDF file.
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Function Generator

This circuit provides a parabolic voltage wave form E repetitively across a charging capacitor 10. This voltage is produced by periodically charging the capacitor with current through a summing transistor 11 and then discharging it through a transistor switch 12.

The summing transistor 11 is connected in a constant current configuration so that the current through it is not affected by the voltage on the charging capacitor 10. The current through the transistor 11 is determined by a current modifier circuit 13 which is shown to the right of point 14. The switch 12 periodically discharges the capacitor 10.

The current modifier circuit 13 has a charging capacitor 15. This is periodically charged from a second summing transistor 16 connected in a constant current configuration and periodically discharged through a transistor switch 17. The resultant voltage across the capacitor 15 varies linearly with time.

By supplying the modifier current to the emitter of the constant current transistor 11, the parabolic voltage wave form E is developed across the charging capacitor 10. The upper wave form is that of switch 12; the middle wave form is that of capacitor 15; the lower wave form is E across capacitor 10

A hyperbolic wave form may be produced by feeding to the summing transistor a plurality of currents which vary exponentially with time.

By suitable selection of the modifier circuit, other wave forms may be produced.

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