The ยูฟ่าเอสซีอาร์ Diaries
The ยูฟ่าเอสซีอาร์ Diaries
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SCRs are mainly Utilized in devices wherever the control of significant electrical power, possibly coupled with substantial voltage, is demanded. Their Procedure helps make them well suited for use in medium- to large-voltage AC ability Handle apps, like lamp dimming, electricity regulators and motor control.
After the SCR commences conducting, no extra gate voltage is required to maintain it while in the ON point out. The minimum amount present required to retain the SCR in the ON state on removal in the gate voltage is called the latching recent.
Temperature triggering happens once the width of depletion area decreases since the temperature is enhanced. Once the SCR is around VPO an incredibly smaller rise in temperature brings about junction J2 to get taken out which triggers the unit.
To ensure that gate triggering to come about, the thyristor must be inside the ahead blocking condition where the utilized voltage is under the breakdown voltage, otherwise ahead-voltage triggering might come about.
A silicon-controlled switch (SCS) behaves just about the identical way being an SCR; but There are some discrepancies. In contrast to an SCR, an SCS switches off every time a positive voltage/input recent is placed on another anode gate lead.
Ahead-voltage triggering happens when the anode–cathode ahead voltage is amplified While using the gate circuit opened. This is named avalanche breakdown, all through which junction J2 will stop working.
An individual tiny good voltage pulse can then be applied concerning the gate plus the cathode. This provides a single gate present-day pulse that turns the thyristor on to its on state. In observe, This is certainly the most common method accustomed to cause a thyristor.
Characteristic curve of a silicon-managed rectifier You can find three modes of operation for an SCR relying upon the เอสซีอาร์4 biasing given to it:
An SCR incapable of blocking reverse voltage is named an asymmetrical SCR, abbreviated ASCR. It generally has a reverse breakdown score in the tens of volts.
SCRs and similar gadgets are utilized for rectification of substantial-ability AC in high-voltage direct current energy transmission. They are also used in the control of welding machines, mainly gas tungsten arc welding and similar processes.
TRIACs have 3 leads: a gate guide and two conducting prospects, generally known as MT1 and MT2. If no recent/voltage is placed on the gate direct, the TRIAC switches off. On the other hand, In case the cause voltage is placed on the gate lead, the TRIAC switches on.
At sufficient voltages, the thyristor alterations to its on point out with minimal voltage fall and enormous forward recent. In this case, J1 and J3 are previously forward-biased.
An SCR is often introduced from blocking method to conduction method in two techniques: Either by growing the voltage among anode and cathode past the breakover voltage, or by applying a good pulse in the gate.
When the used voltage reaches the breakover benefit for J2, then J2 undergoes avalanche breakdown. At this breakover voltage J2 commences conducting, but under breakover voltage J2 gives really higher resistance to the current and the SCR is alleged to get inside the off state.
An easy SCR circuit using a resistive load A straightforward SCR circuit might be illustrated utilizing an AC voltage resource connected to a SCR by using a resistive load. Without having an used recent pulse for the gate of the SCR, the SCR is still left in its ahead blocking condition. This makes the beginning of conduction of the SCR controllable.