Electronic Components

V-FET or Power Mosfets

Power Mosfet-N-channel Power MOSFETs are usually constructed in V-configuration, as shown in figure. That is why, the device is sometimes called the V-MOSFET or V-FET. V-shaped cut penetrates from the device surface almost to the N+ substrate through N+, P and N~ layers, as seen from figure. The N+ layers are heavily doped, low resistive […]

UJT-Uni Junction Transistors

Unijunction transistor (abbreviated as UJT), also called the double-base diode is a 2-layer, 3-terminal solid-state (silicon) switching device. The device has-a unique characteristic that when it is triggered, its emitter current increases re generatively (due to negative resistance characteristic) until it is restricted by emitter power supply. The low cost per unit, combined with its […]

Shockley Diode

The four-layer diode, also called the Shockley diode after its inventor William Shockley, is essentially a low-current SCR without a gate. It is classified as a diode because it has only two external terminals through anode and cathode. Because of its four doped regions it is often called a P-N-P-N diode. The basic structure, two […]

Photoconductive cells

The photoconductive cell is a two terminal semiconductor device whose terminal resistancewill vary (linearly) with the intensity of the incident light. For obvious reasons, it is frequently called a photoresistive device. The photoconductive materials most frequently used include cadmium sulphide (CdS) and cadmium selenide (CdSe). Both materials respond rather slowly to changes in light intensity. […]

LASCR-Light Activated SCR

LASCR or Photo SCR Light activated SCR (LASCR) or a Photo SCR is just an ordinary SCR except that it can also be light triggered. Most LASCRs also have a gate terminal for being triggered by an electrical pulse just as a conventional SCR. The basic construction of an LASCR is shown in figure. The […]

Silicon Unilateral Switch

The diac and the silicon bilateral switch are grouped as bilateral or bidirectional devices because they can breakover in either direction. There are also breakover devices which breakover in only one direction; they fall in the category of unilateral or unidirectional breakover devices. Although unilateral breakover devices are more frequently employed in SCR triggering, they […]

Silicon Bilateral Switch

Silicon Bilateral Switch Silicon bilateral switch (SBS) is another breakover device which is capable of triggering triacs, and it is popular in low-voltage trigger control circuits. They have breakover voltages lower than those for diacs, ± 8 V being the most popular rating. V-I characteristic curve of an SBS is similar to that of the […]

SCS-Silicon Controlled Switch

Silicon Controlled Switch Silicon controlled switch (SCS), like the SCR, is a unilateral, four layer three junction P-N-P-N silicon device with four electrodes namely cathode C, cathode gate Gx, anode gate G2 and the anode A, as shown in figure. Infact, the SCS is a low power device compared with the SCR. It handles currents […]

GCS-Gate Controlled Switch

GCS As mentioned earlier, low-current drop out is the normal way in which the SCR is turned off. Gate-controlled switch is designed for easy opening with a reverse-biased trigger. A gate controlled switch (GCS) is closed by a positive trigger and opened by a negative trigger (or by low-current drop out). Gate-controlled switch circuit is […]

Gate Turn Off Switch

Gate turn-off switch (GTO) is, like an SCR, is a four layer, three junction semiconductor device with three external terminals, namely, the anode, the cathode and the gate, as illustrated in figure. The basic construction, schematic symbol of a GTO are shown is figures respectively. Although the graphic symbol is different from either the SCR […]