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Transistor Tunnel Diode Bistable Trigger

IP.com Disclosure Number: IPCOM000097111D
Original Publication Date: 1962-May-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Buelow, FK: AUTHOR [+3]

Abstract

This circuit comprises a single transistor connected in emitter follower configuration. It has a pair of tunnel diodes in its emitter circuit. It is bistable in response to data and clock signals. Sufficient current change takes place between the two trigger states to drive the incandescent indicator.

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Transistor Tunnel Diode Bistable Trigger

This circuit comprises a single transistor connected in emitter follower configuration. It has a pair of tunnel diodes in its emitter circuit. It is bistable in response to data and clock signals. Sufficient current change takes place between the two trigger states to drive the incandescent indicator.

Transistor T is connected to a current source at its collector and responds to clock input signal Vc at its base. Paired diodes D1, D2 are connected at their common connection to load circuit RL and to the data signal input circuit. Tunnel diode D3 is connected in this input circuit to act as a buffer to data currents larger than required, preventing the trigger from setting erroneously. When sufficient data current is drawn, D3 switches producing a voltage across resistor Rs. This specifies the magnitude and direction of the current Is flowing in it. This current flows into RL. The operating points D1 and D2 are shown in waveform diagram
A. When Vc is coupled to the base of T, the peaks of the diode pair characteristic decrease and switching of these diodes occurs. There is then very little voltage drop across Rs.

When the data current returns to zero, at some later time, as shown in waveform diagram B, D3 switches back to its original state producing a voltage of the opposite polarity across Rs. The direction of Is also reverses so that the diode pair switches to its original state when Vc pulsates. The clock pulse is eithe...