Search Results
| Search type | Search syntax |
|---|---|
| Tags | [tag] |
| Exact | "words here" |
| Author |
user:1234 user:me (yours) |
| Score |
score:3 (3+) score:0 (none) |
| Answers |
answers:3 (3+) answers:0 (none) isaccepted:yes hasaccepted:no inquestion:1234 |
| Views | views:250 |
| Code | code:"if (foo != bar)" |
| Sections |
title:apples body:"apples oranges" |
| URL | url:"*.example.com" |
| Saves | in:saves |
| Status |
closed:yes duplicate:no migrated:no wiki:no |
| Types |
is:question is:answer |
| Exclude |
-[tag] -apples |
| For more details on advanced search visit our help page | |
Results tagged with zero-crossing
Search options answers only
not deleted
user 20218
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.
8
votes
zero cross detector missing zero cross
The basic problem is that your AC source is not-isolated from ground. If it were then there would be no problem when you add the 10 kohm resistor that I recommended.
So, you have one incoming AC lin …
- 473k
4
votes
Accepted
Why 2 zero-crossing detection circuits in heater?
What could be the reason for having those 2 separate circuits?
The opto U1 produces a square wave output in phase with the incoming AC and is probably used as a zero crossing detector by the MCU. …
- 473k
4
votes
Accepted
How to sense the zero crossing of current?
I am trying to sense the power factor angle using microcontroller.
To do this with any degree of accuracy and for unknown load conditions is a lot tricker than you think. Consider the following: …
- 473k
3
votes
Will this zero-cross detection circuit work?
The rise/fall time of the opto is about 20 microseconds (1000 ohm load) and the time when the rectified voltage is close to zero is maybe 2 degrees of one cycle. At a 20ms period of AC, a couple of de …
- 473k
3
votes
Accepted
ZCD with LM358 not working
The LM358 is powered from 5 volts and you are forcing an input signal from the bridge that is rectifying a 12 V AC voltage. This usually means the LM358 will never work again.
The operational input r …
- 473k
3
votes
Dimming light idea
This should turn the triac on and off with a duty cycle of 60%
Triacs turn off when their main current falls below a threshold. In other words, you can turn on a triac from a control pin but, you ca …
- 473k
3
votes
Will a low-pass filter make zero-crossing detection less precise?
Will a low-pass filter make zero-crossing detection less precise?
I assume you are comparing one signal against another and that all signals are processed using the same hardware. In other words, …
- 473k
3
votes
Accepted
Tachometer IC that does not require zero-crossings?
I realize this circuit requires a VR pickup sensor, and so the
LM2907/LM2917 must rely on triggering off of zero-crossings.
The data sheet tells you that a zero cross does not trigger anything: -
Y …
- 473k
3
votes
Does a signal that doesn't change polarity charge a capacitor?
Secretly I hope the capacitor does not effect the UART signal, because
adding a circuit for zerocrossing adds (logically) more components to
the PCB.
Well, your secret is out now and be prepared for …
- 473k
3
votes
Accepted
Why this ZCD not working?
When the input goes negative you are exceeding the input common-mode voltage range (as specified in the data sheet) and strange things will happen: -
In other words, your input is going below 0 volts …
- 473k
2
votes
Automatic calibration of a zero cross detector latency
A calibration value can be automatically created if you consider using a spare analogue input on the PIC. Connect this input to a potted-down and biased version of the AC and let the PIC process mean …
- 473k
2
votes
Accepted
Would this lazy zero cross detector work?
Make sure your resistors are rated for the voltage you are applying. Some resistors are only rated at 100V peak so watch this one.
With a total LED resistance of 125 kohm and the specified input capa …
- 473k
2
votes
Accepted
DIY zero-crossing circuit, how crucial are component values?
There's a basic problem with the circuit around the 2N3904 transistor and how it gets biased (more further down)...
For the resistors yes, and given the applied voltages, two in series will likely be …
- 473k
2
votes
Accepted
Zero Crossing Detection of ~ 400 kHz Signal with MCU
If you are dealing with an analogue signal and trying to convert it to a suitable square wave for frequency measuring you have to consider the effects of noise and implement some form of hysteresis so …
- 473k
2
votes
Would I need a zero-crossing SSR for a reflow oven controller?
The design/guide is for using the oven AND a fan controlled from seperate zero-crossing SSRs. The oven is just a resistive heating element and could be controlled from a non-zero-crossing switch but i …
- 473k