TTL Logic Questions?

A circuit is using 2 parallel open collector outputs to drive some TTL inputs, the more inputs you add:
1) the LOW- level current that may be allowed to flow through the pull-up resistor increases
2) The High-level current that flows through the pull-up resistor decreases
3) the pull-up resistor has a smaller range of acceptable values
4) th High-lever open collector outputs must source more current to the inputs


My next questions is:
Which one of the statements is FALSE:
1) A TTL LOW level output sinks current from a connected TTL input
2) A High level totem pole output sources current to a connected TTL input
3) a High level open collector output coureces curent to a connected TTL input
4) a Low level TTL input sinks current from a +5 V through the base of a input transistor

I know these may seem simple enough but until I can fully grasp what is going on in these circuits questions like these give me a problem. Thanks for the help in advance. I have read quite a bit about these circuits but it just hasn't clicked yet but I will keep grinding but I need some help.

hello,

Take a look at this link:
http://www.twysted-pair.com/74xx.htm

This is a link from the EDUCYPEDIA page about TTL:
http://www.educypedia.be/electronics/digitaltechnologyttl.htm

There are more digital topics over there:

Digital electronics:
Arithmetic circuits D/A-A/D converters Number systems Codes and decoders Flip flops Technology Counters and registers General overview Technology-CMOS Digital logic Memories Technology-TTL Timers and oscillators

Greetings,
Bertus