The field-effect transistor (FET) is a transistor that uses an electric field to control the electrical behaviour of the device. FETs are also known as unipolar transistors since they involve single-carrier-type operation. Many different implementations of field effect transistors exist. Field effect transistors generally display very high input impedance at low frequencies. The conductivity between the drain and source terminals is controlled by an electric field in the device, which is generated by the voltage difference between the body and the gate of the device.
Photo Darlington is a phototransistor that is related to Darling transistor family also called Darlington phototransistor or photodarlington. The photodarlington transistor provides a much higher degree of sensitivity when compared to other phototransistors, but this is at the expense of response time and frequency response.
In electronics, the Sziklai pair (also known as a complementary feedback pair (CFP) or "compound transistor", and as a "pseudo-Darlington") is a configuration of two bipolar transistors, similar to a Darlington pair. In contrast to the Darlington arrangement, the Sziklai pair has one NPN and one PNP transistor, and so it is sometimes also called the "complementary Darlington". The configuration is named for its early popularizer, George C. Sziklai.