A photoelectric amplifier comprising a photodiode having an anode connected to a gate of a first FET and a cathode connected to a gate of a second FET, with the second FET having a source-gate interconnection so as to be self-biasing. The photodiode cathode is connected to a high impedance feedback loop, including an output transistor, which is connected back to the photodiode anode. In a preferred embodiment, further included is a feedback circuit gain controlling transistor having a base driven by the feedback circuit and a current electrode connected to the source of the first FET.

Photo-electric conversion circuit

Speed measuring method and system based on increment type photoelectric encoder

: The patent describes a frequency multiplier with a fixed multiplication factor comprising at least one p-n semiconductor junction diode and an electron beam for irradiating the p-portion of the diode. One form of the invention has diodes arranged in pairs, the input frequency modulating the beam to sweep it back and forth across the diodes once per input cycle. Another form has a mask across the face of a diode with undulations in the mask acting to vary the amount of current flow in the diode as the beam sweeps back and forth across the mask. A further form of the invention comprises sweeping the beam in a circle in one direction only either over a series of diodes or over a single diode which is covered with a mask.

Frequency multiplier and high frequency generator

A photoresponsive device employing a silicon photocell to excite on illumination of the photocell a transistor in a discriminator circuit and drive the transistor from a non-conducting to a conducting condition. The photovoltaic output of the silicon cell is added to the potential of the direct current potential of a bias source to exceed the threshold conduction potential of the discriminator transistor. Thermostability is achieved by employing a transistor in the bias source of identical type and similar characteristics to the discriminator transistor. The discriminator transistor has an emitter-collector circuit which includes a load resistor, and the output which is developed across the load resistor is amplified by a common emitter transistor amplifier circuit. The transistor of the amplifier circuit is a N-P-N, while the transistor of the discriminator circuit is a P-N-P type. A switching transistor is used in the common emitter circuit of the discriminator transistor. In the optical encoder disclosed, a separate discriminator circuit is employed for each silicon photodiode, but a single direct current bias source is employed. The switching transistors are pulsed, either sequentially or at the same time to interrogate the photodiodes.

Curt M Lampkin

Papers

Analog to digital encoder