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A silicon-controlled switch (SCS) behaves nearly the same way as an SCR; but there are a few differences. Unlike an SCR, an SCS switches off when a positive voltage/input current is applied to another anode gate lead. Unlike an SCR, an SCS can be triggered into conduction when a negative voltage/output current is applied to that same lead.
Tunnel diodes and Gunn diodes are examples of components that have negative resistance. Hysteresis vs single-valued: Devices which have hysteresis; that is, in which the current–voltage relation depends not only on the present applied input but also on the past history of inputs, have I–V curves consisting of families of closed loops. Each ...
Current–voltage characteristic of a p–n junction diode showing three regions: breakdown, reverse biased, forward biased. The exponential's "knee" is at V d. The leveling off region which occurs at larger forward currents is not shown. A diode's current–voltage characteristic can be approximated by four operating regions. From lower to ...
The electrons and holes travel in opposite directions, but they also have opposite charges, so the overall current is in the same direction on both sides of the diode, as required. The Shockley diode equation models the forward-bias operational characteristics of a p–n junction outside the avalanche (reverse-biased conducting) region.
The Shockley diode equation relates the diode current of a p-n junction diode to the diode voltage .This relationship is the diode I-V characteristic: = (), where is the saturation current or scale current of the diode (the magnitude of the current that flows for negative in excess of a few , typically 10 −12 A).
Like an SCR, when a voltage pulse is present on the gate terminal, the device turns on. The main difference between an SCR and a Triac is that both the positive and negative cycle can be turned on independently of each other, using a positive or negative gate pulse. Similar to an SCR, once the device is turned on, the device cannot be turned off.
The characteristics and components of ripple depend on its source: there is single-phase half- and full-wave rectification, and three-phase half- and full-wave rectification. Rectification can be controlled (uses Silicon Controlled Rectifiers (SCRs)) or uncontrolled (uses diodes). There is in addition, active rectification which uses transistors.
Comparison of an SCR and GTO of same rating Characteristic Description Thyristor (1600 V, 350 A) GTO (1600 V, 350 A) V T on: On-state voltage drop 1.5 V 3.4 V t on, I g on: Turn-on time, gate current 8 μs, 200 mA 2 μs, 2 A t off: Turn-off time 150 μs 15 μs