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Oscillator Transformer Circuit

IP.com Disclosure Number: IPCOM000090400D
Original Publication Date: 1969-Apr-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Joyce, JM: AUTHOR

Abstract

This circuit for a high-frequency push-pull oscillator is provided with a separate negative base bias winding consisting of a saturable core reactor utilized to turn off the alternately conducting transistors. The circuit provides starting current I5 to turn on either transistor Q1 or Q2 depending upon the initial state of the saturable core Sr 1. Q1 conducts collector current I1 through winding N1 of power transformer T1 and the positive feedback winding N3 drives Q1 into saturation. During the time that Q1 is on,bias current I3 is conducted through winding N1 of SR 1. When SR 1 saturates in the direction shown, Q1 is reversed biased by the negative voltage at winding N5. When Q1 turns off, the voltages of the secondary windings N3...N6 go to zero and starting current I5 now turns on transistor Q2.

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Oscillator Transformer Circuit

This circuit for a high-frequency push-pull oscillator is provided with a separate negative base bias winding consisting of a saturable core reactor utilized to turn off the alternately conducting transistors. The circuit provides starting current I5 to turn on either transistor Q1 or Q2 depending upon the initial state of the saturable core Sr 1. Q1 conducts collector current I1 through winding N1 of power transformer T1 and the positive feedback winding N3 drives Q1 into saturation. During the time that Q1 is on,bias current I3 is conducted through winding N1 of SR 1. When SR 1 saturates in the direction shown, Q1 is reversed biased by the negative voltage at winding N5. When Q1 turns off, the voltages of the secondary windings N3...N6 go to zero and starting current I5 now turns on transistor Q2. Feedback winding N4 drives Q2 into saturation and bias current I4 resets the saturable reactor in the direction shown. The performance of the second half-cycle of the circuit is the same as that in the first half-cycle with winding N6 providing the negative voltage to turn off Q2 at the end of the second half-cycle. The core of T1 is made of a ferrite material and is not permitted to saturate by setting the frequency of the saturable reactor higher than the saturation frequency of the transformer.

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