Category: OPTOELECTRONIC DEVICES

Optocoupler Circuit Operation

Optocoupler Circuit Operation: An Optocoupler Circuit Operation (optoelectronic coupler) is essentially a photo-transistor and an LED combined in one package. Figure 20-35(a) and (b) shows the typical circuit and terminal arrangement for one such device contained in a DIL plastic package. When current flows in the LED, the emitted light is directed to the phototransistor, […]

Photodarlington Working

Photodarlington Working: The Photodarlington Working shown in (Fig. 20-33) consists of a phototransistor connected in Darlington arrangement with another transistor. This device is capable of producing much higher output currents than a phototransistor, and so it has a greater sensitivity to illumination levels than either a phototransistor or a photodiode. With the additional transistor involved, […]

Phototransistors Working

Phototransistors Working: A Phototransistors Working is similar to an ordinary BJT except that its collector-base junction is constructed like a photodiode. Instead of a base current, the input to the transistor is in the form of illumination at the junction. Consider an ordinary BJT with its base terminal open-circuited, [Fig. 20-27(a)]. The collector-base leakage current […]

Solar Energy Conversion Diagram

Solar Energy Conversion Diagram: The Solar Energy Conversion Diagram, or solar energy converter, is essentially a large photodiode designed to operate solely as a photovoltaic device and to give as much output power as possible. To provide maximum output current, solar cell surface areas are much larger than those of signal photodiodes, Typical solar cell […]