Electronic timer circuit including linear ramp function generator and/or progress pointer

Claim 2

A linear electronic timer comprising: means for providing a reference potential; linear ramp function generating means for developing, when energized, a second potential which linearly varies in value with elapsed time toward the value of said reference potential; said generating means including output circuit means for carrying said linearly varying second potential; capacitance means connected to said output circuit means for storing a voltage; actuable circuit means connected to said capacitance means for, upon actuation, linearly discharging said capacitance means to thereby generate said linearly varying second potential across said output circuit means; means for energizing said generating means; and means for comparing said reference potential and said second potential and developing an output signal when the values of said two potentials are substantially equal; said linear ramp function generator includes: first and second transistors of the same conductivity type; a third transistor of an opposite conductivity type than said first and second transistors; each of said transistors having input and output circuit means, said output circuit means of said first and third transistors being respectively coupled to the input circuit means of said third and second transistors; and said capacitance means coupling said output circuit means of said second transistor with the input circuit means of said first transistor.

Claim 3

A linear electronic timer comprising: means for providing a reference potential; linear ramp function generating means for developing, when energized, a second potential which linearly varies in value with elapsed time toward the value of said reference potential; means for energizing said generating means; and, means for comparing said reference potential and said second potential and developing an output signal when the values of said two potentials are substantially equal; said linear ramp function generator includes: first and second transistors of the same Conductivity type; a third transistor of an opposite conductivity type than said first and second transistors; each of said transistors having first, second and control electrodes; said first electrodes of said first and third transistors being respectively directly coupled to the control electrodes of said third and second transistors, and said second electrodes of said first, second and third transistors being coupled in common; and a capacitor coupling said first electrode of said second transistor with the control electrode of said first transistor; said generator exhibits high voltage gain and has a high input impedance and further includes an input resistor for coupling the control electrode of said first transistor to a direct current voltage source through said high impedance, said input resistor being of sufficient value that the input voltage thereacross is substantially greater than the voltage developed across the second and control electrodes of said first transistor, whereby as said second potential linearly varies with elapsed time said input resistor compensates for variations in the values of said input voltage and said capacitor due to variations in temperature.

Claim 4

A linear electronic timer comprising: means for providing a reference potential; linear ramp function generating means for developing, when energized, a second potential which linearly varies in value with elapsed time toward the value of said reference potential; means for energizing said generating means; and, means for comparing said reference potential and said second potential and developing an output signal when the values of said two potentials are substantially equal; said linear ramp function generator includes: first and second transistors of the same Conductivity type; a third transistor of an opposite conductivity type than said first and second transistors; each of said transistors having first, second and control electrodes; said first electrodes of said first and third transistors being respectively directly coupled to the control electrodes of said third and second transistors, and said second electrodes of said first, second and third transistors being coupled in common; and a capacitor coupling said first electrode of said second transistor with the control electrode of said first transistor; said generator exhibits high voltage gain and has a high input impedance and further includes an input resistor for coupling the control electrode of said first transistor to a direct current voltage source through said high impedance, said input resistor being of sufficient value that the input voltage thereacross is substantially greater than the voltage developed across the second and control electrodes of said first transistor, whereby as said second potential linearly varies with elapsed time said input resistor compensates for variations in the values of said input voltage and said capacitor due to variations in temperature.