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0
votes
2answers
73 views

HCPL3700 - 220V sensing circuit

I want to use HCPL3700 optocoupler for sensing 220V (line). I design a circuit but I want to ask some questions. HCPL3700 is an open-collector output so I pull-up Vout. In AC voltage sensing some ...
0
votes
0answers
90 views

What's the best way to detect zero crossing in this design?

The design that I am talking about: I want to be able to detect the zero point with an MCU of which pin can withstand only 3.3 V. I'll forgo optocoupler because A. I want everything to be as cheap as ...
2
votes
5answers
1k views

DIY zero-crossing circuit, how crucial are component values?

I want to build this circuit, taken from here, and I'm wondering exactly how crucial exact component values are. I don't have any 220k, 22k, or 4.7k resistors. I'm wondering if I can substitute two ...
2
votes
1answer
3k views

How Zero Crossing optoisolator to work with 220VAC?

I want to use a H11AA1 to detect Zero Crossing, but I am not sure how circuit should look like. How much voltage should LED receive inside H11AA1? Here is datasheet: http://www.vishay.com/docs/83608/...
10
votes
4answers
16k views

TRIAC dimmer, circuit design help (resistive load)

Okay guys, I've been tasked with making a light-dimming control system for a 240V heat lamp dissipating around 250W. I need to adjust the heat output on the lamp by control from a microprocessor. I'm ...
4
votes
2answers
3k views

What does 'random phase' means in a triac driver?

I'm using this triac driver to control a triac. In its datasheet it says 'provide random phase control of high current triacs [...]'. What does that mean? It doesn't have zero-crossing detection?
29
votes
2answers
14k views

How can I detect a power outage with a microcontroller?

I have the following power supply configuration: AC MAINS -> UPS -> 24V POWER SUPPLY -> 5V VOLTAGE REGULATOR -> PCB (microcontroller). What's the best solution to detect the power outage on the mains ...
5
votes
4answers
10k views

120VAC 60Hz Zero Cross Detector

I'm designing a digital phase-controlled light dimmer, and I need a zero-crossing detector circuit. From what I've read, it's a bad idea to wire the AC main directly to the microcontroller through a ...
14
votes
5answers
5k views

detecting zero cross in ac?

I need to detect zero crossing for a soft starter. A long while ago, I have done it using a 1 Mega ohm resistor directly connected to micro controller at one side and live power at another side. I was ...