Optical coupling silicon-controlled switch circuit diagram

Published:2011/3/30 22:58:00 Author:Ecco | Keyword: Optical coupling, silicon-controlled switch | From:SeekIC

The figure 1(a) shows the optical coupling silicon-controlled switch circuitry. The trigger voltage of silicon-controlled rectifier(SCR) is from resistance R, and the the value is decided by the current of phototriode, controlled by input voltage. The circuitry is simple, and there is reliable electronic isolation between the input and output. The figure 1(b) shows the switching circuitry in which load controll is pure resistance. And the value of R1 in the figure is decided by the formula as below: R1＝V/1．2A，1．2A is bidirectional switching rated current. When the voltage of main network is 220V, V＝/2·220=308V，then R1=308/1．2=250Ω. So the specification of silicon-controlled rectifier(SCR) is chosed according to the the value of R1.When the load of switching circuitry is inductive, it needs to increase corresponding components to promise the circuitry's normal work, as the current passing the inductive is different from the phase of voltage. It is shown as below: The switching circuitry shown in the figure 2 is especially suitable for distant control.



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