Interference-free multivibrator switching circuit using saturated undoped transistors with large base-to-emitter capacity

Claim 2

In a multivibrator-type switching circuit using two transistors with interconnecting circuit means operative to switch the transistors alternately from a cutoff to a saturation condition, the improvement comprising the provisions of a base circuit for each transistor arranged to supply to the base of each transistor in a saturated condition a base current at least five times the maximum collector current of the transistor when saturated divided by the minimum physically realizable common emitter current gain of the transistor, said transistors being of a type having a large base-to-emitter capacitance during saturation conditions and an absence of doping in the base-toemitter region whereby the major part of the saturated base-toemitter charge for each transistor flows out of the base lead of the transistor.

Claim 3

A multivibrator-type switching circuit as claimed in claim 1 wherein the transistors have a saturation time constant of at least 1 microsecond.

Claim 4

A multivibrator-type switching circuit comprising first and second transistors, each having an emitter, a collector and a base, said transistors are undoped in the base-to-emitter region, a direct voltage supply having first and second terminals, two collector loads in series respectively with the collectors of the transistors between the collectors and said first terminal, first and second resistors connecting respectively the collectors of the first transistor to the base of the second transistor and the collector of the second transistor to the base of the first transistor, third and fourth resistors connecting the bases of the first and second transistors respectively to said second terminal, a connection between the emitters of the two transistors and ground, a fifth resistor in series with a first rectifier between the collector and the base of the first transistor, a sixth resistor in series with a second rectifier between the collector and base of the second transistor, and an input circuit capacitively connected to the junction of the fifth resistor and first rectifier and the junction of the sixth resistor and second rectifier, said transistors having a saturation time constant of at least 1 microsecond and having a large base to emitter capacity when in saturation, and the loads and first, second, third and fourth resistors being arranged so that the base current fed into each transistor, when it is in the saturated condition, is between five and 10 times the maximum collector current divided by the minimum common emitter current gain.

Claim 5

A multivibrator-type switching circuit comprising first and second transistors, each having an emitter, a collector and a base, said transistors are undoped in the base-to-emitter region, a direct voltage supply having first and second terminals, two collector loads in series respectively with the collectors of the transistors between the collectors and said first terminal, first and second resistors connecting respectively the collectors of the first transistor to the base of the second transistor and the collector of the second transistor to the base of the first transistor, third and fourth resistors connecting the bases of the first and second transistors respectively to said second terminal, a connection between the emitters of the two transistors and ground, a fifth resistor in series with a first rectifier between the collector and the base of the first transistor, a sixth resistor in series with a second rectifier between the collector and base of the second transistor, and an input circuit capacitively connected to the junction of the fifth resistor and first rectifier and the junction of the sixth resistor and second rectifier, said transistors having a saturation time constant of at least 1 microsecond and having a large base to emitter capacity when in saturation, and the loads and first, second, third and fourth resistors being arranged so that the base current fed into each transistor, when it is in the saturated condition, is between five and 10 times the maximum collector current divided by the minimum common emitter current gain.