A Silicon Controlled Rectifier - A PNPN or NPNP semiconductor device that once triggered stays in permanently conductive state until the current is removed. USed in protective circuits and chopper style light dimmer switches. Also know as a thyristor.
Questions tagged [scr]
200 questions
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How to mount a TO-200AB
I'm looking into high power SCRs. The two common cases i'm finding are TO-209AB and TO-200AB.
The TO209AB are straight forward to mount and connect.
The other, TO-200AB is strange looking and doesn't provide any mounting information. It appears…
vini_i
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Turning on SCR without latching it
The picture shows a typical SCR circuit. I have already simulated this circuit in multisim. Since multisim assumes this to be an ideal SCR (zero voltage drop for example,) the characteristics may not be the same in practical situation. I'm asking…
Sayan
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Scr gate resistor
as we know in transistors, current controls current, in JFET voltage controls current, but how about SCR? I have learnt that the gate can be triggered using both voltage and current (called gate triggering voltage or gate triggering current). So can…
Sayan
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Trouble with simulating an SCR
I was reading about SCRs and I'm trying to simulate 2N5060 SCR but having some issues when I plot the currents and voltages:
First by looking at the datasheet, I set the R4 to keep the gate current a bit less than 200uA.
For V2 I set the on time…
user1245
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Confused with turn on time definition of an SCR
The following question I encountered is asking about the minimum time for applied voltage to the gate of an SCR to turn it ON:
And below is the solution:
I can understand the solution looking for the pulse duration for the SCR current to reach…
user1245
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SCR circuit falsely triggered during capacitor charging
I am building a coil gun. Above is the complete schematic of the voltage boost circuit plus the trigger circuit.
Not shown in the schematic, there is a push button switch between the regulated +9V and the Vcc of the 555. When the switch is pressed,…
dgreenheck
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What is the purpose of the unijunction transistor in this circuit?
Trying to figure out the purpose and functionality of this circuit. Apparently, this is some sort of temperature controller. There is no information on parts values or the load type (heater, probably?). But my question is, what does the unijunction…
Jimmy Falcon
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Turn on Mosfet by SCR
can the Mosfet be turned on as shown on picture? My desire is voltage on M1 fire the SCR stay on forever.
V2 is ramp voltage.
user208862
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What is minimum holding current in CT based SCR switch?
I am looking to use a CT based SCR switch to switch an AC contactor. The switch specs list the following:
Off state voltage: 240 VAC RMS max.
Minimum holding current: 10 mA.
On state current: 1.0 AAC RMS max. continuous
Off state leakage: 50 ua @…
OhtohV2
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How does this Snap Circuits SCR circuit work?
I came across some custom Snap Circuits projects. One of them was a homemade SCR out of non polarized capacitors, two bipolar (NPN) and (PNP) transistors, some resistors, and an L.E.D. I am very familiar with how an SCR works and what it does. I am…
james
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Scr threshold voltage
recently I was going through a thyristor's data sheet, I saw one unfamiliar parameter called "threshold voltage " , can somebody explain what it is?
Sayan
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reversed-functioned scr
Like in a scr say in thyristors or triacs we know we can turn the scr "on" after a certain anode-cathode break-over voltage depending on the current present at the gate.But I want to know whether there is device or circuit which remains off if the…
Sayan
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Triac phase control
It's a triac phase control circuit, my book says. I know the conduction angle or the firing angle can be adjusted by adjusting the gate current in both cycles. but the question is what is the purpose of the capacitor here? How it's controlling the…
Sayan
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Why crowbar is needed?
I know it is to protect sensitive load, but doesn't the zener diode in the power supply already do that? zener diode inside the power supply already limits the voltage to its breakdown voltage. Why do we need to short the powersupply in order to…
across
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SCR for load bank switching?
I'm building a load bank for testing high power lead acid batteries, and expect to pass up to 800 amps at 12 VDC. I could do it with contactors but would like to use an SCR with a pot and allow the current to be ramped up with the pot. Any thoughts?
