Electrical engineers all over the world would bet anything for a better datasheet search engine. It’s such an underserved market that there are still rooms for improvement. Although there are hundreds of websites that supply datasheets in the form of PDF like DatasheetCatalogue, AllDataSheet, and many others, recently launched DatasheetLib follows a different approach from […]
Remote Display Multimeter Fluke 233. Using the Fluke233 remote digital thermometer you can work at two places in same time. Such a multimeter is very in suitable performing test and measurements at hazardous environments. Standing on ladders, tangling long test cables, calling a second guy for at the desired location and perform the test/measurement from
UJT Characteristics The static emitter charÂacteristic (a curve showing the relation between emitter voltage VE and emitter current IE) of a UJT at a given inter base voltage VBB is shown in figure. Â From figure it is noted that for emitter potentials to the left of peak point, emitter current IE never exceeds IEo .
In this article, we learn about UJT (Uni Junction Transistor) in detail. We cover a lot about UJT like – what is basically a UJT, how they differ from other transistor models, how to construct a UJT, operation & working of a UJT, how to build applications of UJT and so much more. Lets dive
Light activated SCR (LASCR) or a Photo SCR Â 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 elecÂtrical pulse just as a conventional SCR. The basic construction of an LASCR is shown in figure. The schematic symbols most commonly
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
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 (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 diac, but it
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. You can find more
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 in milli amperes
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 shown
Introduction to IGBT-Insulated Gate Bipolar Transistors Insulated gate bipolar transistor (IGBT) is a new high conductance MOS gate-controlled power switch. The fabrication process is similar to that of an N-channel power MOSFET but employs an N-epitaxial layer grown on a P+ substrate. In operation the epitaxial region is conductivity modulated (by excess holes and electrons)
Introduction to CMOS-Complimentary Metal Oxide Semiconductor FET’s Complementary metal oxide semi-conductor devices are chips in which both P-channel and N-channel enhancement MOSFETs are connected in push-pull arrangement. The basic connections for CMOS are shown in figure. Above figure shows various CMOS connections especially N-channel and P-channel CMOS connections. In this circuit, two MOSFETs (P-channel MOSFET and
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 material, while
Although DE-MOSFET is useful in special applications, it does not enjoy widespread use. However, it played an important role in history because it was part of the evolution towards the E-mode MOSFET, a device that has revolutionized the electronic industry. E-MOSFET has become enormously important, in digital electronics and. In the absence of E-MOSFET’s the
We know that when the gate is biased negative with respect to the source in an N-channel JFET, the depletion region widths are increased. Theincrease in the depletion regions reduces the channel thickness, which increases its resistance. The net result is that drain current ID is reduced. If the polarity of VGG were reversed so
From the circuit named “looking into the drain” of the FET it is seen (for small signal operation) an equivalent circuit consisting of two generators in series, one of – u times the gate signal voltage Vin and the second (u + 1) times the source-signal voltage Vs and the resistance rd + ((a +
What is a Junction Field Effect Transistor? A JFET is a semiconductor with 3 terminals, available either in N-channel or P-channel types. It is unipolar but has similar characteristics as of its Bipolar cousins. Instead of PN junctions, a JFET uses an N-type or P-type semiconductor material between the collector and emitter (Source & Drain).
As already mentioned in Field Effect Transistors (FET) , JFET’s are of two types, namely N-channel JFETs and P-channel JFETs. Generally N-channel JFETs are more preferred than P-channel. N-channel and P-channel JFETs are shown in the figures below. Basic Construction. The structure is quite simple. In an N-channel JFET an N-type silicon bar, referred to
Introduction to FET-Field Effect Transistor So far we have discussed the circuit applications of ordinary transistors, in which both holes and electrons take part. This is the reason that these are sometimes called the bipolar transistors. Such transistors have two main drawbacks namely low input impedance because of forward biased emitter junction and considerable noise
The photoconductive cell is a two terminal semiconductor device whose terminal resistance will vary (linearly) with the intensity of the inciÂdent 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
