bagusdj
Member level 3
hey guys, im trying to assembling 4n26 opto transistor for zero cross detector. i configure it this way. zcd is going to my mcu external interrupt.
if i used 10k on R1, i will get voltage in zcd in amount of 3v. with this resistor, the time required to form a zero cross square wave is huge.
i tried to use 820 Ohm on R1, the time required for pulsing is less, but voltage that flows through zcd is about 0.8V.
for AT89S52, what is the minimum voltage required to trigger external interrupt? in data sheet it only mentions operating voltage for mcu is 4-5.5V

if i used 10k on R1, i will get voltage in zcd in amount of 3v. with this resistor, the time required to form a zero cross square wave is huge.
i tried to use 820 Ohm on R1, the time required for pulsing is less, but voltage that flows through zcd is about 0.8V.
for AT89S52, what is the minimum voltage required to trigger external interrupt? in data sheet it only mentions operating voltage for mcu is 4-5.5V
