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Oscillator

IP.com Disclosure Number: IPCOM000093454D
Original Publication Date: 1967-Sep-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Clapper, GL: AUTHOR

Abstract

This oscillator is capable of operation up into the megacycle range with good power handling capability and utilizes a single transistor only. The oscillator has a sinusoidal output with a peak-to-peak amplitude of about 14 volts at a low impedance. The oscillator is self-starting and can employ a crystal for precise frequency control.

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Oscillator

This oscillator is capable of operation up into the megacycle range with good power handling capability and utilizes a single transistor only. The oscillator has a sinusoidal output with a peak-to-peak amplitude of about 14 volts at a low impedance. The oscillator is self-starting and can employ a crystal for precise frequency control.

Inductor L and capacitor C are connected in series with output load register
R. Transistor T1 is connected across C. The base of T1 is connected to ground through resistor R1 and capacitor C1 connected in parallel. In those instances where a crystal is desired for precise frequency control, the crystal is connected across R1C1 circuit in the base circuit of T1. With the values shown, the circuit provides a sinusoidal output at a frequency slightly above one megacycle. If the crystal is employed, the frequency is controlled and equals one megacycle. Load capacitance CL is approximately 500 picofarads.

For initial conditions, assume that all the capacitors are discharged and all voltage sources are at ground or 0 volts. When voltages are applied, the emitter of T1 drops towards -6 volts causing T1 to conduct, thus effectively shorting C. Base current charges C1 as the base follows the emitter and CL charges through resistor R. Current builds up in L as the voltage at the collector of T1 drops towards -6 volts.

At some point near -6 volts, the emitter current reduces and equals the base current causing the collector current...