Linked Questions

9
votes
5answers
2k views

Why are bulky SCR power controllers used when the same can be achieved with a relay?

This is kinda noob question. I recently got an SCR Power controller (WATLOW DIN-a-mite DB20-24CO-0000 Style B). This is the first time I actually got to test an SCR controller for myself. The input ...
5
votes
4answers
1k views

PWM 1Hz on solid state relay

I'm about to build a pid heating controller with a 1kW heater and a solid state relay. The ESP8266 can go down to 1Hz pwm frequency. So hopefully I can vary the number of active cycles per second, ...
3
votes
2answers
5k views

Why is zero crossing detector is used in some AC control circuits?

Zero crossing occurs when the line voltage is changing its polarity, from positive to negative, or vice versa. What I understand is, to fire the triac properly the firing circuit and the AC line ...
4
votes
3answers
11k views

A question on zero crossing versus random-fire SSRs

Figure 1. I have the above mechanism, where I control a single-phase fan motor's switch. I mean instead of a mechanical switch, an AC/DC SSR is switching ON or OFF from a remote place by a constant ...
1
vote
2answers
3k views

Could a “non-dimmable” LED lamp be dimmed with PWM?

I have some experience with house wiring, and more recently gained some experience with 5mm RGB LEDs and an Ardiuno. In that, I learned about PWM for dimming an LED. I suspect that the standard wall ...
0
votes
2answers
3k views

Using AC current to trigger Triac

I am trying to simulate the operation of an optocoupler with a triac to trigger the triac using the AC current. I have come across a few circuits that are all similar: My question is regarding the ...
0
votes
2answers
2k views

Triac drivers with or without zero-crossing detection

I've been looking at this schematic for triac control by varying the gate pulse timing. The description states that the triac switches off automatically at zero crossing and when there is no gate ...
0
votes
1answer
1k views

What is the relation between the mains frequency and the ideal PWM frequency in this circuit?

Below is a triac control circuit used in on-off mode: The mains freq. is 50Hz. The micro-controller PWM frequancy is set to 5Hz in this simulation. Optotriac is triggering the triac. By playing with ...
0
votes
1answer
259 views

Controlling a PSC motor with a triac thermostat

I have a multizone hydronic heating system that has a pump for each zone. The Pumps are Taco 0015 three speed pumps like this one that I am to understand are permanent split capacitor motors. The ...
1
vote
3answers
223 views

A question about triac output of zero crossing SSR relay

In a zero crossing SSR if the output is a triac, would the gate be fired/triggered every 180° or would the gate be applied a constant voltage all the time? I'm asking because in both cases the load ...
0
votes
2answers
156 views

PWM Light Dimmer

So basically I want to build a dimmer circuit. If I connect an optocoupler to the PWM pin on the MCU and a triac to the optocoupler with an incandescent bulb and generate a square wave something like ...