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Which is the best optocoupler for 230V line detection?
I am trying to detect line voltage (230V AC, if the supply is ON/OFF) by a microcontroller with the help of an AC optocoupler. The optocouplers I have evaluated are PC814, H11AA1 and SFH620A-3, out of which I found SFH620A-3 to be more efficient (must be due to the better CTR).
What is the creepage distance for a 240VAC PCB?
What is the required creepage (e.g. trace-to-trace) distance for PCBs handling 240VAC rms? What about 120VAC? This is for UL and CE certification. The standards for PCB Creepage (e.g. the distance across the surface of a PCB between high-voltage connections) are locked up in proprietary, pay-only IEC standards (specifically, IEC Report 664/664A).
Why are creepage and clearance distances so important?
The isolation required between parts with different operating voltages, to prevent against unacceptable risk, is the primary reason for the importance of creepage and clearance distances. Specifically, creepage is the shortest distance between the path of two conductive parts of a medical device and is measures along the surface of insulation.
What should the current be to turn on the opto?
While testing my circuit at various input voltages I found that the opto will start giving fluctuating output when my voltage is 145V. I calculated the voltage and found that for 145V AC and a series resistance of 440K, the current is just 0.33mA which may to be insufficient to turn on the opto.
How is optocoupler used in DC based switching?
In the upper image the internal construction or the TRIAC based opto-coupler is shown. TRIAC is mainly used where AC based control or switching is needed. The led can be controlled using DC, and the TRIAC used to control AC. Opto-coupler provide excellent isolation in this case too.
How is the intensity of the led controlled by optocoupler?
Intensity of the LED directly controls the photo-transistor. Since the LED can be controlled by a different circuitry and the photo transistor can control different circuitry so two independent circuits can be controlled by Optocoupler.
What are the different types of optocoupler symbols?
In the upper image there are two types of symbol, internal construction of Photo-Darlington based opto-coupler is shown. Darlington Transistor is two transistor pair, where one transistor controls other transistor base.
How to hook up a 230V AC mains detection module?
A pull-up resistor is provided for use with microcontrollers (e.g. ESP8266) that do not have an internal pullup resistor. The hardware connections are pretty straightforward. On the low voltage side the + (positive symbol) goes to VCC of microcontroller, – (negative symbol) goes to GND and S goes any digital/interrupt pin.
How to disable zero crossing on AC mains?
By default zero crossing detection is disabled by the use of a 2.2uF capacitor, in order to use the board for zero crossing detection the capacitor needs to be bypassed by cutting the trace shown below. It can be resoldered at any time later to disable zero crossing:
What is the output of a 60 Hz power line?
The output will be a 120 HZ ripple on 60 HZ power lines. After research the H11AA814 is obsolete and can be replaced with a Vishay SFH628 series.
How to sort and filter in an optocoupler?
All 32 rows shown. Click here to reset sorting and filtering. Click the buttons to sort and filter the table. Sort toggles between ascending, descending, and off. Filter by click and drag or ctrl-click to select multiple items.