Abstract: Integrated laser diode devices are utilized as repeater elements and logic circuit elements in fiber optic and other light transfer systems. One embodiment discloses a six layer device (10) which is triggered not by an external electrical gating source, but by an external light source (8, 9) as from an optical fiber. Another embodiment operates a laser diode in a bilateral mode. That is, depending on the polarity of the applied voltage bias V to the device (50), two separate light pulses are emitted from different regions (56, 52) of the crystal. A further embodiment utilizes the semiconductor laser as a logical AND function. When the electrical bias (V) of the device (60) is set so that when at least two external light sources (67, 68) are applied, the device will emit laser light (69). Still another embodiment utilizes two semiconductor laser devices (911, 913) as an astable optical multivibrator (90).

Abstract: A resistor, together with a charging capacitor, is connected in series between the emitters of transistors to constitute an emitter-coupled astable multivibrator to be used with a voltage-controlled oscillator. The resistance of the resistor is given by:R.sub.a =(.tau..sub.d1 +.tau..sub.d2)/2C.sub.awhere C.sub.a is capacitance of the capacitor and (.tau..sub.d1 +.tau..sub.d2) is a delay time during one period of oscillation, as determined by the circuit elements.

Abstract: A programmable oscillator includes first and second transistors having their emitters coupled by a capacitor, and a pair of current sources coupling respective transistors to ground. A switching means is provided having a first state coupling the collector of the first transistor to the base of the second transistor and coupling the collector of the second transistor to the base of the first transistor, and a second state coupling the collectors of the first and second transistors to ground such that when the switching means is in the first state, the first and second transistors switch on and off in alternating fashion, and when the switching means is in the second state the first and second transistors remain on continuously.

Abstract: A computer controlled facility is provided to detect capacitance, and hence defective connections, between a group of wires in a telephone handset cord and terminal blades of plugs connected at both ends of the cord. The test depends upon ascertaining the capacitance between a properly connected terminal blade and wire and the other terminal blade and wire connections to provide exact indications of the terminal blades and wires which are not properly connected. Capacitance is detected by connecting a good wire and blade connection along with another wire and blade in a capacitance network associated with one stage of a free running multivibrator which produces an output wave in accordance with the capacitance between the connected pairs of wires and blades. A delayed pulse is cyclically generated to act in conjunction with the output wave to control a bank of indicator lights to provide an indication of any defective wire to blade connections.

Abstract: A multi-stage astable multivibrator wherein a plurality of astable multivibrators each consisting of two transistors are connected in parallel so that a high output may be derived and a completely rectangular output waveform may be obtained. Diodes are connected to the emitters of the transistors so that the breakdown of the transistors may be prevented.

Abstract: An astable multivibrator circuit having an adjustable pulse width but constant frequency, including a pair of active elements such as transistors for being switched on and off alternately and reciprocally, and a control circuit associated therewith for controlling the multivibrator circuit to derive therefrom a controlled output pulse signal, the pulse width of which is varied without changing the frequency thereof.

Abstract: A pulse generator circuit including first, second and third transistors in which the first and second transistors are associated with resistors and capacitors to form an astable multivibrator coupled power supply. The third transistor is connected between the astable multivibrator and a variable resistor, the latter being connected to the power supply and adapted to control the pulse width of an output signal derived from the astable multivibrator whereby the pulse width of the output signal is controlled to be substantially uniform regardless of changes in the power supply voltage and ambient temperature.