Questions tagged [zero-crossing]

Zero-crossing refers to detecting the point at which a sine wave reaches the zero point of magnitude. In AC circuits it corresponds to the point at which no voltage is present so switching at that point reduces interference.

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zero cross detector missing zero cross

I'm trying to make a zero cross detector. I used the schematic below as a reference.(schematic from http://microcontrollerslab.com/zero-crossing-detector-circuit-using-pic-microcontroller/) However ...
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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 ...
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67 views

Core-less transformer for Zero-crossing detection

If possible, what are calculations and precautions involved in making a simple transformer without core? The only purpose of this transformer is to trigger an opto-coupler for zero-crossing detection ...
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Difference between Zero-Crossing Optoisolator and Regular Optoisolator

I am trying to find any documentation on what the purpose is of a Zero-Crossing Circuit TRIAC Optoisolator. The datasheets don't explain the concept well enough. If you do answer, please include ...
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Audiable pops when switching DC biased audio signal

In my previous question, I have asked how to DC bias audio signal for a crosspoint audio switching matrix (Switch array (crosspoint) and DC biasing of audio signal). I am using the following circuit ...
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570 views

Is it possible to use Microchip's ZCD (Zero cross detect) circuitry in an isolated SMPS?

Let's say you have a device which is fed by AC line voltage and features an isolated SMPS. The switcher outputs 5 VDC, and that powers a PIC micro. I'm curious how is the Microchip's ZCD (Zero cross ...
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581 views

Current zero cross detection circuit off of triac

I need help modifying the circuit below. The assumption in this circuit as it stands is that AC Hot would be common to GND and then MT2 of the triac would go through a light source to AC Neutral. ...
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96 views

Zero crossing detector inconsistency

I designed the following zero crossing detector using an FOD819S optocoupler (U5): The source of the optocoupler is connected to a MB6F full-bridge rectifier (D2) which is supplied by a 9V ...
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Controling a Washing Machine AC Motor Using a Relay

I would like to control the motor of my washing machine using an Arduino. It's an old washing machine with a mechanical controller and an AC motor connected to a 12.5 uF run/start capacitor. According ...
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71 views

Best TRIAC for zero cross detection

I already asked this question Triac BT 136 getting shorted when load is given to T1. When I referred this link, I understood rate effect is the root cause for our problem. To avoid this either we ...
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ZCD with PIC 18LF45K40

I want to implement phase angle control for a single phase ac fan. To achieve that we need a ZCD circuit interfaced with a microcontroller to get a pulse at zero crossing. As our circuit has some ...
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Zero Crossing Signal Timing

I have a zero crossing circuit for dimming lamps exactly like the below According to my calculations: \$ I_{R7} = \frac {V}{R} = \frac {3.3}{10k} = 0.33~mA\$. Considering TCMT1109 transfer ratio ...
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Art of Electronics zero-crossing circuit question

I'm trying to make sure I understand how this circuit works fairly well before I read on. Here is the diagram: Here are some of the things I am thinking about this circuit: Because input goes to ...
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1answer
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zero-crossing detection: to optocouple or not to optocouple?

That is the question. Most of the diagrams I have seen on the interwebs are of the opto-coupling school of thought: But the AVR182: Zero Cross Detector application note just throws in the resistors ...
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1answer
44 views

Tapping into a 5.1V transformer for a zero-crossing detection circuit

I want to make myself a reflow oven following more or less this guide: http://andybrown.me.uk/2015/07/12/awreflow2/ Here is the zero-crossing detection circuit diagram: Thing is I would like to cut ...
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Static VAr Compensation

I have to design a 3 phase Reactive Power Compensation System with using only reactors, no capacitor is needed. Total capacity is 505kVAr, but 475kVAr will be done with contactors, rest (30kVAr) will ...
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Digital Dimmer With Microcontroller

I want to build a digital dimmer for resistive Loads. I have found this circuit for that: The input voltage is 220VAC 50Hz. The red box in the picture is for ...
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1answer
143 views

Zero-crossing in AC with DC offset signal

Introduction I have a project about measuring the voltage, current and power factor of an electrical system. I had designed a system that allows the microcontroller to measure the peak of an AC with ...
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358 views

Arduino PID and AC controlling

I'm trying to make my own PID temperature controller using Arduino. Arduino PID library outputs a PWM signal. I need to control 230VAC using this PWM like a triac phase angle controlling. If I use a ...
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Using zero crossing detector for brightness control of several loads

Zero cross detector(IC H11AA1) generates a pulse exactly at zero crossing of AC wave. I am trying to control the brightness of several bulbs(nearly 48 loads). I have 5 different states for them. At ...
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258 views

Zero-crossing signal inconsistent timing

I have an ESP-07 with NodeMCU firmware connected to a dimming module with a zero-crossing pin. The current frequency should be 50Hz, which means that the time between two zero crossing should be 10ms,...
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Zero crossing detection and Light dimmer

I am confused by zero crossing detection of opto-triac. I know what is the zero crossing detection or switch. (ZCS) Zero crossing detects what is the point that wave is going to positive to negative ...
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951 views

Would I need a zero-crossing SSR for a reflow oven controller?

I'd like to follow this guide to create a reflow oven controller: https://apollo.open-resource.org/mission:resources:picoreflow But I am confused on the zero-crossing SSR. Does it need to be zero-...
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Zero-crossing detection

I'm doing a circuit that controls a charge for TRIAC, with zero detection. Whenever I tested the circuit, regardless of what I was sending from the microcontroller, TRIAC always sent all the current ...
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189 views

direct ac mains to MCU pin for zero crossing detection

to detect Zero Crossing of ac mains, can i connect an EFM8 pin configured as input directly to 220V ac via a resistor?
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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 ...
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4answers
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Arduino 230v Light bulb dimming

Hey guys i have done a lot of research and testing on different circuits for 230v(50hz) or 220v light dimming, but i cant get my arduino to dim my light. This is the last thing i tried. made this ...
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Counting the number of zero crossing using arduino uno

will this code work to display the frequency of input signal of zero crossing detector? ...
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Zero Crossing Circuit Input Resistor

I'm building a dimmer, and got some questions about the resistor in the zero cross circuit. My circuit is like the image above, and I'm wondering if in the case of 100V input the current is to small. ...
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1answer
240 views

Why 2 zero-crossing detection circuits in heater?

I reverse engineered the power board of an electric heater. I think, I understand most aspects of this circuit. One thing is not entirely clear to me though: The circuit seems to have two distinct ...
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4answers
546 views

Zero Crossing Detection of ~ 400 kHz Signal with MCU

I want to measure the frequency of a signal using the digital input pins of the NUCLEO-F767ZI. The signal is sinusoidal with an amplitude of 5 V and a frequency ranging from 100 kHz to around 400 kHz. ...
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268 views

Can triac opto-coupler used as a simple optocoupler?

I had more than 50 pcs of MO3041 but in my circuit need operation like 817. I know i can use 817 for DC circuit but i am just want to know if i can use MO3041 in DC circuit. I know there is a simple ...
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543 views

Zero cross circuit exploded

would like to get a feedback on a zero cross circuit as it does not work. Circuit is based on this. 240V AC, 50 Hz Expect that C2 is 50V. R1,R2, R4 are SMD. After connecting to mains and measuring ...
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142 views

Swap main terminals of zero-crossing triac

The question I have is maybe silly, but I cannot find strictly related info. When designing a mains switch with an optotriac driven triac (or discrete SSR for you), during layout I swapped the ...
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888 views

Optoisolator, did I connected it right? (Arduino Uno)

Here is my connection for optoisolator, 2 wires, yellow and red are for AC current. Other 3 in my arduino, orange pin 2, blue ground and red 5V power. And ...
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1answer
540 views

Are these BLDC waveforms making any sense?

I'm trying to drive a BLDC with a microcontroller, a discrete inverter and a sensorless network for feedback. Here's the model I'm using and what ultimatly is my PCBA: I'm driving this thing open ...
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1answer
405 views

Problem in AC fan speed control(using ZCD and Atmega8A) when running on Inverter

I recently built an AC fan speed control circuit using Atmega8a,Triac,2 nos Optocoupler and ZCD method.I am attaching the necessary circuit regarding the triac firing and ZCD.The Atmega is configured ...
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1answer
332 views

How to account for input noise on a zero crossing detector op amp?

To save potential confusion let me start by saying I just started learning opamp theory about a week ago. I'm currently familiar with inverting, non-inverting, summer, and difference opamps. My (...
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1answer
181 views

Mains AC TRIAC offset circuit

I'm designing a fluorescent lamp dimmer circuit which will work with Arduino pro mini. The mcu will detect zero cross from mains outlet and will give out offset for TRIAC. I would just like to get ...
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A problem regarding connecting the grounds within two seperate circuits

Figure 1 I am trying to design the above circuit for my project to create zero crossing detector as shown in the above figure. This configuration was proposed originally by the member named "...
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632 views

Linear power supply + zero-crossing detection on transformer secondary

Having read this comment, I'm a bit concerned about whether one of my projects is going to work: simulate this circuit – Schematic created using CircuitLab The comparator is also inside the uC,...
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How to create a zero crossing detector using a full bridge wave rectified circuit

Currently 1) I have a full bridge wave rectified ac waveform of 10Vmax. 2) I also have a potentiometer adjustable DC waveform. 3) My rail voltages are +12V and -12V. 4) I currently supply my full ...
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how to construct zero cross detecting circuit for line current? [closed]

I am constructing Optocoupler based Zero cross detection circuit for power factor correction.How to find zero crossing of current wave?please recommend the circuits with resistor calculations. ...
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617 views

Will a low-pass filter make zero-crossing detection less precise?

In my application I need to sample a number of bipolar signals coming from piezo sensors, and detect their relative time difference (for multilateration based on difference time of arrival). I expect ...
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Zero Cross TRIAC circuit for regulator fails on voltage spike

I am using a ZC TRIAC circuit to switch and regulate an electric appliance e.g. a table fan, a electric drill etc. I must confirm that proper SNUBBER circuit is used and everything works fine. I ...
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6answers
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Confusion with TRIAC firing and zero crossing point

The reason for firing a TRIAC very close to the zero crossing point is explained as to avoid RF or EMI interference. Below is an excerpt from a book: What I'm having trouble to understand is that, if ...
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When should I fire the TRIAC's gate when controlling an inductive load (AC motor)?

I'm using a combination of opto-triac + TRIAC to control a 230V AC motor with a microcontroller. For detecting the zero-crossing of the voltage I'm using another optocoupler. I know that the AC motor ...
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1answer
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Zero Crossing Optoisolator in Multisim

I'm an electronics hobbist with relatively little experience and I'm playing around with Multisim to try to understand how to manipulate AC waveforms. Specifically, I would like to control the wave ...
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Why do we prefer zero-crossing optotriacs for driving triacs?

I usually see a special type of optotriac which has internal zero-crossing detection circuit in it. This type of optotriac is generally used for driving triacs. But, I don't understand its necessity. ...
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How to test if zero crossing is working?

I used circuit like this: On led I get: 3.3 mA and 1.3V What is the best way to test if zero crossing works with arduino or multimetar?