For this test circuit I am using a SN74161N 4-bit counter.
I am trying to learn digital electronics and have recently bought the Basic Stamp PLC by Parallax.
I have gotten the circuit to work using the Basic Stamp. Now I am trying to build it on a breadboard without the PLC. My question is regarding pull-up and pull-down resistors.
Correct me if I am wrong, but I believe the pins are as follows.
V_IH = 2 volts minimum
V_IL = .8 volts max
The question is not so much what resistor to use, as much as it is how do I go about calculating these resistors.
I am wanting to use a pull-up resistor connected to the CLR pin( which is an active-low ). My power supply is 5V.
I am not sure if this is right, but the max current for the pin is 40uA(again, correct me if I am wrong).
My guess for the maximum possible resistor is:
(5V - 2V)
----------
(40uA/1,000,000uA) -> convert to amperes
= 75,000 ohms
Is this how I would calculate the maximum resistor? How would I calculate the minimum resistor?
Also could someone explain this for pull-down resistors as well?
Any help is much appreciated! Thank you.
I am trying to learn digital electronics and have recently bought the Basic Stamp PLC by Parallax.
I have gotten the circuit to work using the Basic Stamp. Now I am trying to build it on a breadboard without the PLC. My question is regarding pull-up and pull-down resistors.
Correct me if I am wrong, but I believe the pins are as follows.
V_IH = 2 volts minimum
V_IL = .8 volts max
The question is not so much what resistor to use, as much as it is how do I go about calculating these resistors.
I am wanting to use a pull-up resistor connected to the CLR pin( which is an active-low ). My power supply is 5V.
I am not sure if this is right, but the max current for the pin is 40uA(again, correct me if I am wrong).
My guess for the maximum possible resistor is:
(5V - 2V)
----------
(40uA/1,000,000uA) -> convert to amperes
= 75,000 ohms
Is this how I would calculate the maximum resistor? How would I calculate the minimum resistor?
Also could someone explain this for pull-down resistors as well?
Any help is much appreciated! Thank you.