i need some help

[Stud]

hi....I need some help in designing a circuit that can convert a DC
signal( 1 to 5 V) to a TTL signal which can be accepted through the
parallel port of the computer. I originally planned to use the LM 311
and LF 411 comparators along with some other components. Any helpful
advice would be appreciated.

 

[John Popelish]

hi....I need some help in designing a circuit that can convert a DC
signal( 1 to 5 V) to a TTL signal which can be accepted through the
parallel port of the computer.

What about the DC signal do you want to turn into digital states?

I originally planned to use the LM 311
and LF 411 comparators along with some other components. Any helpful
advice would be appreciated.

The LM339 quad comparator is probably better suited to the task. It
has to be powered by at least 6.5 volts if its inputs are to deal with
5 volt signals (the supply needs to be at least 1.5 volts more
positive than the most positive input signal level). A 9 volt battery
would work fine. You may need a 10k pull up resistor between the
output and the positive supply, since these comparators turn on a
switch to the negative supply rail when the - input is more positive
than the + input.