- #1
waltersobchak
- 7
- 0
Hi all,
I am an electrical engineer and feel I should know this (embarrassing!), but I for the life of me still can't quite get this concept.
I understand conceptually the idea behind a pull up or a pull down, in that we want the IC to read a high state, by defaultm in the case of a pull up and low by default in case of pull down. But earlier to day an engineer was saying that we needed a lower pull down resistor to drive a pwm from 3 to 5 volts. I still don't get/understand the connection between a pull up/pull down and pwm signal? I get that its ideal to drive a motor using a pwm signal and a resistor could be used as an impedance to drive the pwm, but i still don't get the use of resistor in pwm to pull it "up" or "down"? an example, links or clarifications would be much appreciated. thanks
I am an electrical engineer and feel I should know this (embarrassing!), but I for the life of me still can't quite get this concept.
I understand conceptually the idea behind a pull up or a pull down, in that we want the IC to read a high state, by defaultm in the case of a pull up and low by default in case of pull down. But earlier to day an engineer was saying that we needed a lower pull down resistor to drive a pwm from 3 to 5 volts. I still don't get/understand the connection between a pull up/pull down and pwm signal? I get that its ideal to drive a motor using a pwm signal and a resistor could be used as an impedance to drive the pwm, but i still don't get the use of resistor in pwm to pull it "up" or "down"? an example, links or clarifications would be much appreciated. thanks