Timing circuit with multiple time constants and switching means to connect and disconnect said time constants selectively

Claim 2

An oscillation generator comprising: A. a unijunction transistor having first and second base terminals and an emitter terminal; B. a timing circuit comprising: 1. a first resistor, and 2. a capacitor connected in series with said resistor to receive charging current therethrough, said capacitor also being connected in series between said emitter and said first base terminal, and said resistor also being connected in series between said emitter and said second base terminal; C. a second resistor; and D. an electronic switching circuit connected to said unijunction transistor to be actuated by current pulses through said transistor, said switching circuit coMprising an output circuit switchable between first and second states by successive pulses from said transistor and connected to said second resistor to connect said second resistor effectively in series with said capacitor to supply additional charging current thereto when said switching circuit is in its first state and effectively to remove said second resistor from said capacitor when said switching circuit is in its second state.

Claim 3

a capacitor connected in series with said resistor to receive charging current therethrough, said capacitor also being connected in series between said emitter and said first base terminal, and said resistor also being connected in series between said emitter and said second base terminal; C. a second resistor; and D. an electronic switching circuit connected to said unijunction transistor to be actuated by current pulses through said transistor, said switching circuit coMprising an output circuit switchable between first and second states by successive pulses from said transistor and connected to said second resistor to connect said second resistor effectively in series with said capacitor to supply additional charging current thereto when said switching circuit is in its first state and effectively to remove said second resistor from said capacitor when said switching circuit is in its second state.

Claim 4

a capacitor connected in series with said resistor to receive charging current therethrough, said capacitor also being connected in series between said emitter and said first base terminal, and said resistor also being connected in series between said emitter and said second base terminal; C. a second resistor; and D. an electronic switching circuit connected to said unijunction transistor to be actuated by current pulses through said transistor, said switching circuit coMprising an output circuit switchable between first and second states by successive pulses from said transistor and connected to said second resistor to connect said second resistor effectively in series with said capacitor to supply additional charging current thereto when said switching circuit is in its first state and effectively to remove said second resistor from said capacitor when said switching circuit is in its second state.

Claim 5

The generator of claim 1 in which said output circuit comprises a transistor connected in series with said second resistor to form a second series circuit in parallel with said first resistor.

Claim 6

a capacitor connected in series with said resistor to receive charging current therethrough at a predetermined rate, said capacitor also being connected in series between said first and second electrodes; C. means to connect said third electrode to a source of potential different from the potential of said first electrode and of a polarity to permit conduction between said first and third electrodes when said second electrode reaches a predetermined potential; D. means connected to said first resistor to supply charge to said capacitor at said predetermined rate to increase the voltage thereacross in the proper polarity to cause said second electrode to reach said predetermined potential; E. a second resistor; and F. an electronic switching circuit connected to said solid state device to be actuated in response to current pulses through said solid state device and comprising an output circuit switchable between first and second states by successive pulses through said solid state device and connected to said second resistor to supply current therethrough to charge said capacitor at a rate higher than said predetermined rate when said output circuit is in its first state and at said predetermined rate when said output circuit is in its second state in which said second resistor is effectively disconnected from said capacitor.

Claim 7

a capacitor connected in series with said resistor to receive charging current therethrough at a predetermined rate, said capacitor also being connected in series between said first and second electrodes; C. means to connect said third electrode to a source of potential different from the potential of said first electrode and of a polarity to permit conduction between said first and third electrodes when said second electrode reaches a predetermined potential; D. means connected to said first resistor to supply charge to said capacitor at said predetermined rate to increase the voltage thereacross in the proper polarity to cause said second electrode to reach said predetermined potential; E. a second resistor; and F. an electronic switching circuit connected to said solid state device to be actuated in response to current pulses through said solid state device and comprising an output circuit switchable between first and second states by successive pulses through said solid state device and connected to said second resistor to supply current therethrough to charge said capacitor at a rate higher than said predetermined rate when said output circuit is in its first state and at said predetermined rate when said output circuit is in its second state in which said second resistor is effectively disconnected from said capacitor.

Claim 8

The generator of claim 1 in which said switching circuit comprises a terminal switchable between a constant high voltage and a low voltage and said second resistor is connected in series between said terminal and the common junction of said first resistor and said capacitor.

Claim 9

The generator of claim 3 comprising, in addition: a diode connected in series with said second resistor to allow current to flow through said second resistor only to charge said capacitor in the same sense as current through said first resistor.

Claim 10

The oscillation generator of claim 1 comprising, in addition: a variable voltage source connected to one of said base terminals to adjust the voltage at which said unijunction transistor becomes conductive as said capacitor charges up.

Claim 11

The oscillation generator of claim 1 in which said first and second resistors are high precision resistors having resistance values within approximately 1% of a nominal value.

Claim 12

The oscillation generator of claim 6 comprising, in addition: a voltage divider comprising a potentiometer, one of said base terminals being connected to the arm of said potentiometer to control the voltage at which said unijunction transistor becomes conductive as said capacitor charges up, said capacitor being of relatively low precision and having a capacitance that may differ more than 20 percent from a nominal value.

Claim 13

The oscillation generator of claim 1 comprising, in addition: a load resistor in series with said second base terminal, said switching circuit being connected to the junction between said load resistor and said second base terminal to be actuated by current pulses through said transistor and said load resistor.

Claim 14

The oscillation generator of claim 1 comprising, in addition: A. terminals for connection to a source of direct voltage, said timing circuit being connected across said terminals; B. a second series circuit connected across said terminals and comprising a second capacitor and a third resistor, said switching circuit comprising a reset terminal connected to the junction of said second capacitor and said third resistor to receive a reset signal when said terminals are connected to a source of direct voltage.

Claim 15

The oscillation generator of claim 9 in which said output circuit comprises a first output terminal to connect said second resistor effectively in series with said capacitor when said first output terminal is in said first state, said first output terminal being switched back and forth between said first state and said second state at a predetermined pulse repetition rate, and a second output terminal switchable between first and second states at a repetition rate one-half the repetition rate of said predetermined repetition rate, said oscillation generator comprising, in addition: a NOR gate having a first input terminal connected to said first output terminal and a second input terminal connected to said second output terminal of said switching circuit, and a driver circuit connected to the output of said NOR gate.

Claim 16

The oscillation generator of claim 10 comprising, in addition: A. a third output terminal on said output circuit to provide a third series of pulses having a repetition rate one-half the repetition rate of pulses at said second output terminal; and B. a second driver circuit connected to said third outPut terminal.

Claim 17

The oscillation generator of claim 11 comprising, in addition: A. a fourth output terminal providing pulses having a repetition rate one-half the repetition rate of pulses at said third output terminal; B. a fifth output terminal providing pulses having a repetition rate one-half the repetition rate of pulses at said fourth output terminal; C. a second NOR gate having a first input terminal connected to said fourth output terminal and a second input terminal connected to said fifth output terminal; and D. a third driver circuit connected to the output of said second NOR gate.

Claim 18

An oscillation generator comprising: A. a solid state device comprising first, second, and third electrodes; B. a timing circuit comprising:

Claim 19

An oscillation generator comprising: A. a solid state device comprising first, second, and third electrodes; B. a timing circuit comprising: