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The safest way would be to use two step down transformers and resistive dividers to scale the AC voltage down. Then you can safely feed it into your MCUs ADC, comparator, etc.pablome said:I want to compare the voltages, frequency/phase with some circuit and feed it to the microcontroller(motorlla 68hc11e9)
www.electronics-made-chin said:,i really don't understand the electronics even though i learned some
when i was in school
Then you have the option of more RAM making it easier to compare the frequency, phase and amplitude using software if you digitize the AC two waveforms with the ADC.Id be using the MCU in Expanded Chip mode.
Why can't you do it in software?But my ordeal is to make a circuit that does the comparing.
You could use a PLL if you wanted to I guess.For frequency...60Hz I was wondering again if there is a simple comparing circuit?
You'd need to convert the AC to a squarewave using a schmitt buffer before feeding it to a input capture pin.The MCU has Input Capture to read the period, or waveform. Dont know what circuit would be needed for that.
Definitely not! The IRFZ20s gate can only handle 20V or so and there is no electrical isolation from the mains making this very dangerous for you and the HC11. Use a transformer to isolate and stepdown the lethal mains voltage. A pair of small AC wallwarts, rectifier, some extra filtering and a resistive divider/load are all you need to interface the HC11s ADC to the 120VAC sources. Make sure you get a wallwart without a built in rectifier so you can measure the AC frequency too.IRFZ20 for waveform signal...(regarding that, can 120V go in to Gate, 5V to Drain and pull up resistor 1K form Source to ground, source going to I/P Capture.?)