Hi
how much is the input impedance of the TTL logic devices, for example if you have a transistor feeds a signal to a 7404 (for example) how you will deal with the input impedance of the 7404 when you make your calculations?
we hear that the TTL family has high input impedance in order not to sink too much current but the question is how much that high impedance is it 1 M or 2 M or what?
Any Ideas, reviews, comments?
Regards.
Anderson
LS reduced the max. input current by a factor of four, increasing the standard logic circuit fanout from 10 to 40.
Only a few types of standard 74 are still in production, while 74LS is available in a large type variety. Because the
price is a multiple of 74HC types now, they are rarely used for new designs.