Can I connect the N/O pin ( 12.8 V when relay on ) to the Arduino input pin using a resistor ?If so, is my guess of a 390 ohm resistor correct ? ( 12.8V to 5V 20mA )
My (very limited) thinking was that, just as a resistor would reduce the power for a LED, so it could also reduce the power for an input pin.
Do you have a diagram or link for a voltage divider for this type of application ? All I need to know is when the external relay is powered - that is, when there is 12.8V on the NO contact.
Use something relatively large, but not extremely large like 5K for Z1 and 10K for Z2.http://www.raltron.com/cust/tools/voltage_divider.asp
Looking at the calculator, if I put R1 = 5000 and R2 = 10000 then the output voltage is 8.533 -- wouldn't this kill my Arduino ?
If I switch the 5k and 10k around, it shows 4.267 output volt.
Please enter a valid email to subscribe
We need to confirm your email address.
To complete the subscription, please click the link in the
email we just sent you.
Thank you for subscribing!
via Egeo 16