Questions tagged [scr]
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.
224 questions
0 votes
1 answer
19 views
How to simulate back-to-back CLA80E1200HF SCR's starting with TRIAC_parms.asy and TRIAC_parms.SUB simulation files, modifying them from the datasheet
I am trying to run a spice simulation of the CLA80E1200HF SCR, where I am attempting to control 220V RMS 10A RMS Inductive and resistive loads using LTSpice under Wine wine-10.0 (Ubuntu 10.0~repack-...
- 129
0 votes
1 answer
50 views
What is the advantage of the L0103DE triac versus two SCR's wired back to back, and how can the reverse-gate-current turn-on for Triacs be determined?
Following my LTSpice simulation of the L0103DE triac: I see that this Triac appears to act just the same as two SCR's wired back-to-back (see its datasheet link here). I am a little bit confused by ...
- 129
0 votes
1 answer
102 views
Lowest triac dimming possible without a microprocessor
The usual triac dimmer circuits cannot fully reduce power to zero. The diac trigger voltage can be lowered below the typical 20V (for 120Vrms US mains power), and the RC time constant can be ...
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1 vote
1 answer
92 views
This is a single phase SCR controlled Reactor. Simulation load is RL instead of fan motor
My problem is that I can't adjust the angle. When I adjust the angle, signal at output aurduino move but output at RL (fan motor) doesn't move as adjusted. I don't know how to fix it. green is output ...
- 21
4 votes
3 answers
286 views
Changing a contactor controlled heater circuit to a silicon-controlled rectifier controlled heater circuit
The original design (BEFORE) controls a heater bank with the controller switch S5. The system is designed to maintain a tank temperature within a narrow range and turn off above the range and on below ...
1 vote
2 answers
162 views
SCR conduction angle problem
Figure 1 This problem is from a book. Consider the SCR 90° phase control circuit shown in Figure 1. The SCR is to be ...
- 1,345
1 vote
1 answer
152 views
How do I know the voltage drop?
I recently made this circuit for a personal project of mine. I wanted to calculate the voltage drop prior to printing the PCB, but I wasn't sure how so I just went with it. And sadly, the voltage ...
- 51
3 votes
1 answer
71 views
SCR Gate Leads Twisting Still Mandatory on Thicker Sheathed Wire?
I have always put my SCRs in a twisted pair with a 3/4" lay (19.05mm lay). It is what the drawings I have seen from 1999 and beyond specify. Reaffirming this specification are the UL,ETL and ...
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4 votes
2 answers
320 views
On/off motor controller. Shorting the SCR doesn't turn it off
My son has built a motorised car at school using a small DC motor, powered by two AA batteries and using two switches, one at each end. The idea is that the green one at the front will cause it to ...
2 votes
1 answer
77 views
AC high current PCB traces
I'm making a circuit that rectifies ( full wave ), with a center tap transformer. Here is my design: As you can see, I want to control the sinusoidal with SCR phase control. My concerns are because ...
0 votes
2 answers
206 views
Using IGBTs for controlling heating loads
I know traditionally antiparallel connected SCRs (Thyristors) are used in phase-angle control mode to control the heat delivered to an industrial furnace or to control heating loads. Can the same be ...
0 votes
1 answer
85 views
Why does adding an LCD to my Arduino project break the controlling of the SCR?
I found this project which is about controlling the firing angle of SCR using Arduino and it works well. https://simple-circuit.com/arduino-scr-half-wave-controlled-rectifier/ Then I modified the code ...
- 1,980
1 vote
3 answers
388 views
AC power failure alarm light
I wanted to make a simple circuit that shows an indicator light to glow when a load is switched OFF. When I turn OFF both the switches for the load then the indicator light should turn ON glowing that ...
- 832
4 votes
2 answers
219 views
SCR not latching when triggered [closed]
I am attempting to design a circuit to discharge an electrolytic capacitor through a bleeder resistor when someone breaks the line of sight between an IR emitter and phototransistor as a safety ...
- 87
0 votes
1 answer
86 views
How the SCR junction J2 is reversed biased even though n section of J2 is not connected to any voltage?
I am confused about how the Junction J2 for the connection above can be reverse biased. The book I have only says that the junctions J1 and J2 are in forward biased but does not explain it. I need ...
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