A method and circuit for controlling the amplification in a radiation-detecting avalanche diode in which the diode generates electrical signals dependent upon the received radiation. These electrical signals are fed to evaluating means and a control signal is derived from the diode having a frequency which differs from the frequency used in the evaluation means. The amplitude of the control signal is compared with a preset value and the supply voltage of the diode is varied in dependence upon this comparison for controlling amplification of the diode.

An insulated gate field effect transistor compatible encoder circuit employs a field effect transistor and a lateral bipolar transistor to reduce the number of transmission lines or pins necessary to transmit information to an insulated gate field effect transistor integrated circuit employing such encoder circuit as its input. The input to the encoder circuit is coupled to both the gate of a field effect transistor and the emitter of a bipolar transistor. When a negative voltage is transmitted to the input, the field effect transistor turns on; when a positive voltage is transmitted to the input, the bipolar transistor is turned on; and when no voltage is transmitted to the input, neither transistor is turned on. The outputs of the transistors are then gated to provide three distinct logic inputs, from the single input, for the insulated gate field effect transistor integrated circuit.

The present negative impedance two terminal network is embodied by two three terminal amplifiers, for example, one of which is a field effect transistor and the other is a bi-polar transistor, wherein the emitter-collector circuit of the bi-polar transistor and the source-drain circuit of the field effect transistor are connected in series with each other. The two terminals of the network are formed by the base and by the collector of the bi-polar transistor. Said collector is also connected to the gate terminal of the field effect transistor. A control voltage source is preferably connected between said base of the bi-polar transistor and the drain terminal of the field effect transistor, whereby said negative impedance is differentially adjustable by varying the control voltage.

A circuit for generating a negative voltage includes: a bipolar transistor including, a) an N type collector region, b) a P type base region, and c) an N type emitter region, the base region width between the emitter region and the collector region being less than about 5,000 angstroms and the dopant concentration of the base region being in the range of about 1-10.times.10.sup.18 atoms/cm.sup.3 ; means for applying a reference potential to the base region; and means for applying a bias potential to the emitter region so as to generate a negative output potential at the collector region. The circuit can likewise comprise a PNP bipolar transistor biased to generate a negative voltage. The circuit can be used on integrated circuit chips to provide a complementary voltage, thereby obviating the requirement for separate, complementary power supplies.

In order to provide compensation for changes in the ambient temperature and supply voltage for an electronic circuit, such as a pulse generator circuit made up of MOSIC structure, a field effect transistor circuit includes a high value resistor and an enhancement and depletion type MOSFET, connected in parallel. The drain electrodes of the MOSFETs are connected to the power supply through the resistor and are also connected to the gate electrode of a depletion type load MOSFET which is the load transistor for an enhancement type MOSFET. When the compensating circuit is provided in a pulse generator circuit, instability in the oscillating frequency of the pulse generator due to changes in ambient temperature and supply voltage is overcome and the difference in the oscillating periods for the various MOSICs are decreased.