Abstract: The collector currents of first and second junction transistors which have base electrodes biased at the same quiescent potential and have emitter electrodes connected via respective emitter degeneration resistances to a common point, are adjusted relative to each other. This is done by applying linearly temperature-dependent voltages in adjustable ratio with each other to the emitter degeneration resistances. This makes it so that the adjustment of the relative values of the collector currents is substantially unchanging over a temperature range.

Abstract: A single adjustable control is commonly connected with each of a plurality of feedback channels, which are selectively coupled in an amplifier circuit to provide the latter with different basic gains, to adjust the respective basic gains of the amplifier circuit by corresponding fractional or proportional amounts of respective ranges of permissible gain chain for each channel, thereby simultaneously to correct or to calibrate each channel for different amounts of drift of the like.

Abstract: A normally-closed temperature sensitive switch which is heat coupled to the output transistors of an amplifier, is connected in series with a zener diode and the operating coil of a relay. When the voltage applied to the series circuit, which is the same voltage as applied to the amplifier, is insufficient to cause breakdown of the zener diode, the relay remains inactivated, and a pair of relay contacts across a feedback resistor of the output transistors remains closed. This keeps the output transistor off so that transients (which are the response of the amplifier to the rapid change in operating voltage when the amplifier is first turned on or when it is turned off) are substantially reduced. When the voltage reaches a given level at or close to the nominal operating voltage level, the relay is activated and the output transistors are turned on. When the temperature reaches a value such that the switch opens, the relay is inactivated and the output transistors are thereby turned off.

Abstract: An amplifying system comprises an amplifier having a certain constant gain, a first variable attenuator through which an input signal for this system is inputted to the amplifier, and a second variable attenuator through which the output signal of the amplifier is delivered. The over-all gain of the system is variable from the minimum gain to the maximum gain by gang-operating the two variable attenuators. The two variable attenuators are of such a construction that the attenuation factor of the first attenuator is substantially variable in the operation range near the middle of the variable gain whereas that of the second attenuator is substantially variable in the operation ranges near the minimum and maximum of the variable gain. When the input signal level is low, the second attenuator functions in the near-maximum range, and when high, the first attenuator functions in the middle range, thus delivering an output signal at the rated level.

Abstract: A so-called charge sensitive amplifier is used as a pre-amplifier for a semiconductor detector. A field-effect transistor (FET) is used as the input stage of the amplifier, wherein the gate terminal of the FET is fed back from the output of the amplifier and the drain terminal of the FET is grounded through a capacitor and connected to a constant current source to make the drain voltage change correspond to the gate potential. The gate potential is self-stabilized.

Abstract: A system for driving a display device having photo elements driven by pulsed current from pulsed current sources in which the firing voltage or operating voltage of the photo elements differs from the extinction voltage thereof. The system includes apparatus for setting the voltage applied to the photo elements to a value less than the extinction voltage at a time near the trailing edge of the pulsed current.

Abstract: A gain control circuit is connected between an output terminal of a transistor detector circuit for audio-frequency or voice signal and an audio amplifier circuit. The gain control circuit comprises a control transistor having an output electrode at which an output potential is produced which is lowered correspondingly as the potential at the output electrode of the detection transistor is decreased, and is utilized for controlling the gain of the audio amplifier circuit. The gain control circuit further comprises time constant circuit, for controlling the control time and the restoring time of the potentials at the output electrodes of the above two transistors and a switching circuit.

Abstract: Electronic apparatus is disclosed suitable for integrated circuit fabrication and comprising shunt voltage regulation. The electronic apparatus may be a radio receiver which uses an unregulated current source for its supply voltage. The power amplifier of the audio amplifier has a pair of conventional large area push-pull output transistors which are connected in shunt with the supply. In accordance with the invention, shunt voltage regulation of the supply voltage is achieved by sensing a change in the supply voltage using a zener diode for a voltage reference and then altering the idling current in the output transistors in response to changes in current flow through the zener diode. In consequence of increases in idling current, the output stages shift from class B toward class A operation and shunt regulate the supply voltage. The zener diode is arranged to provide both stabilization of the full supply voltage and the centering voltage of the push-pull output amplifier.

Abstract: An R.F. amplifier circuit having a high selectivity with a simple and inexpensive construction is provided. An R.F. choke coil acting as a bias supplying element is connected to a collector of an amplifying transistor to supply it with an optimum biasing current for a high electric field strength. A first capacitor is connected in parallel, at a high frequency, with the R.F. choke coil, which is connected to an LC tuning circuit through a second capacitor. A resonance frequency of the R.F. choke coil and the first capacitor is chosen to be sufficiently lower than that of the LC tuning circuit to maintain a single tuned circuit while at the same time an output impedance of the amplifying transistor is stepped up by the first and second capacitors to insure a high quality factor.

Abstract: A feed-forward amplifier with an input arranged to receive wide-band signals and an output to supply a linearly amplified version of these has two parallel signal paths arranged between such input and output, one of the signal paths includes a cascade connection of a signal amplifier and a delay network and the second signal path includes an error amplifier, an error extraction circuit having a directional coupler in which an input side has a first pair of conjugate first and second ports and is connected partly to the input of the feed-forward amplifier and partly to an output of the signal amplifier and an output side has a second pair of conjugate third and fourth ports, the fourth port being connected to an input of the error amplifier, and an error injection circuit which has a first and a second input connected to an output of the delay network and to an output of the error amplifier, respectively and an output connected to the output of the feed-forward amplifier, the error extraction circuit having th

Abstract: The connections between the two inputs of an amplifier and the two outputs of a signal source as well as between the outputs of the amplifier and the inputs of a downstream output element into which the amplifier delivers a signal are inverted periodically and simultaneously and integration is carried out between the outputs of the amplifier and the inputs of the output element. In addition, the inputs of the amplifier are short-circuited periodically, the frequencies of inversion and of short-circuiting being multiples of each other.

Abstract: A transistor differential amplifier circuit includes a pair of NPN type amplifying transistors operated by a constant current source commonly connected to their emitters, and a pair of PNP type load transistors inserted in the collector circuits of said amplifying transistors, respectively. The load transistors are commonly biased with a constant voltage to operate within their saturation regions when input signals supplied on respective bases of the amplifying transistors are balanced, whereby pulse signals with a controlled duty ratio are obtained from the respective collectors of the amplifying transistors.

Abstract: In differential input DC gain amplifiers with high input impedance, a capacitive attenuator is built-in in order to reduce the amplifying effect on the AC component due to interference by the industrial power lines. Such attenuation is obtained by feeding back through cross capacitors the AC signal at one output to the input on the opposite side so that the ratio of the differential outputs to the differential inputs for the AC component is substantially unity.

Abstract: This invention pertains to an emergency lighting circuit that operates with a high pressure, gaseous-discharge lamp and associated ballast. When the gaseous-discharge lamp goes out, after once being ignited, sufficient current is supplied to an incandescent light or lights to maintain illumination to the area normally illuminated by the lamp. The device for providing this current may vary, but generally incorporates a voltage breakdown means that receives higher voltage from the ballast when there is failure of the gaseous-discharge lamp than when the arc therein is struck. A preferred embodiment also lights the incandescent lights during initial warm-up of the gaseous-discharge lamp. The incandescent lights may also be used in a cold environment to maintain the gaseous-discharge lamp sufficiently above an ambient temperature level to make possible initial striking of the arc in the lamp when ambient temperature conditions might otherwise prevent it.

Abstract: A high pressure mercury vapor lamp having an outer bulb with a plural-phosphor coating on the inside surface thereof. A first phosphor provides for emission peaks within the range of wavelengths between 440 and 540 nm and contains strontium chloroapatite, barium magnesium aluminate, strontium chlorosilicate, barium magnesium aluminate, or barium strontium silicate, each activated with di-valent europium. A second phosphor includes yttruim vanaphosphate activated with tri-valent europium which has emission peaks between 600 and 720 nm.

Abstract: In a transistor amplifier circuit comprising a common-emitter amplifier transistor, a collector load resistance has one end connected with the collector of the transistor, a constant-current circuit is connected with the collector of the transistor, and an output of the transistor amplifier circuit is derived from the collector. The constant-current circuit supplies a constant current which is substantially equal to the d.c. emitter current flowing through the transistor and a d.c. voltage which establishes a d.c. voltage level of the output is applied to the other end of the collector load resistance, whereby no d.c. current is permitted to flow through the resistance.

Abstract: A protective coupling circuit is located between the D.C. supply voltage the amplifier components of a push-pull switching amplifier to suppress transients created during switching. The coupling circuit comprises a power supply filter with an inductor coil and capacitor, and circuitry for limiting the voltage on the individual switching elements and the output coil. Excess voltages caused by transients are fed to the power supply filter. In an alternative embodiment the power supply filter inductor coil is actually an auxiliary winding on the amplifier output transformer rather than a separate coil. This allows for use of some smaller capacity circuit elements.

Abstract: The current gain of a current mirror amplifier (CMA) is trimmed by applying an adjustable potential difference between the base-emitter potentials of first and second transistors of the CMA, this potential difference being substantially linearly proportional to the absolute temperature at which the first and second transistors are operated. The resultant trim maintains itself over a wide range of temperature.

Abstract: A device for measuring the frequency or period of an input signal independent of different frequency noise signals which may be superimposed on the input signal includes a filter circuit having a variable cut-off frequency. The output level of the filter circuit is detected by a level detector, the output of which electrically controls a variable element such as a variable resistor, a variable capacitance diode or the like which is included in the filter circuit. This controls the cut-off frequency of the filter circuit, so as to maintain its output level at a given level. In this manner, an input signal frequency is converted into a corresponding level, utilizing a declining portion adjacent to the cut-off frequency of the frequency response of the filter circuit. The converted level is utilized to vary the cut-off frequency of the filter circuit to maintain its output level constant, thereby automatically changing the cut-off frequency in accordance with the input signal frequency.

Abstract: A pair of complementary field effect transistors are connected at the gates thereof to an input terminal for receiving an input signal and at the drains thereof to an output terminal for producing an output signal. The transistor source electrodes are biased by separate, controlled current sources for controlling the ratio of the source electrode currents in accordance with a parameter of the input signal, which parameter may be voltage or current.