The maximum TTL input high current is between 40uA and 1mA depending on its voltage and it is designed to take this small amount of current. Then how can it be bad to do this?So I can use an external power supply and inject a logic HIGH with the current limit set to MAX all the way ? I thought it was bad to do this
No damage since the logic IC limits the input current but the max allowed input voltage (the supply voltage) must not be exceeded.So I can set the current limit to MAX on the external power supply and it will cause no harm or damage to the logic input TTL or CMOS?
That makes no sense since the gate input is connected to another gate's output and you are shorting that active output which IS BAD. Outputs are not designed to be shorted.My Manager will take a jumper from ground to make a logic low when there is a logic high of +18 or +22 , he will take a jump and jump the input high +22 straight direct to ground. Is this good or bad? no bleeder resistor needed or a capacitor needed with the jumper to ground to make a logic low?
ABSOLUTELY NOT!No, It was the design of the circuit, the NOR GATE can input a +12 volts or a - 12 volts on the input
The NOR gate probably had a 0V and +12V supply. Then its input MUST NEVER be negative, it should be between 0V and +12V.
Maybe you are thinking about an opamp or comparator that can have a plus and minus 12V supply and inputs that can be the same.