SCS stands for Silicon Controlled Switch,SCS is a tetrode, Tetrodes are vacuum tubes with four electrodes thyristor. It has two gates, one anode gate (AG) like a PUT and another cathode gate (KG) like an SCR.
In other words, SCS is a four layer, four terminal pnpn device; with anode A, cathode K, anode gate AG and cathode gate KG.SCS can be turned on by either gate.
When a negative pulse is applied to gate AG, junction J1 is forward biased and SCS is turned on. A positive pulse at AG will reverse bias junction J1 and turns off the SCS. A positive pulse at gate KG turns on the device (just like an SCR) and a negative pulse at KG turns it off (just like a G.T.O.).
Its ratings are about 100 V and 200 mA. This can be operated like an OR gate.
Operation of a Silicon Controlled Switch
When a positive pulse of current is applied to the gate terminal, the NPN transistor turns ON.
This allows current to exit the PNP transistor’s base,hence turning the PNP transistor ON.
Now that both transistors are ON, current can flowfrom anode to cathode—the SCS is turned on.
The Silicon Controlled Switch (SCS) will remain ONuntil we remove the anode-to-cathode current, reversethe anode and cathode polarities, or apply a negative voltage to the anode gate.
The negative anode gate voltage removes thetransistor’s self-sustaining biasing current.
Advantages of Silicon Controlled Switch
High current and voltage handling capabilities.
Fast switching speed.
Precise control over switching operations.
Low power consumption.
Robust and durable design.
Cost-effective compared to alternative switching devices.
Disadvantage of Silicon Controlled Switch
Silicon Controlled Switch (SCS) is its relatively slow turn-off time compared to other solid-state switches.
requirement for a gate current to trigger and control the switch.
Limited Turn-off Capability
High Voltage Drop
Limited Operating Frequency
Limited Voltage Ratings
Applications of Silicon Controlled Switches
Timing, logic and triggering circuits
Pulse generators
Voltage sensors
Oscillators etc.
Unleashing the Power of the Silicon Controlled Switch (SCS)
Reviewed by Rakeshaxe
on
May 17, 2023
Rating: 5
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