What are R_L and C_L in TTL circuit specifications?

[riklund]

Hello!
I am wondering if anyone knows what R_L and C_L on a TTL circuit means? I think it is load resistance and load capacitance, but how are they connected to the TTL? I am specifically thinking about a 74LS74 Dual Positive-Edge-Triggered D Flip-Flop.

 

[yungman]

Remember each input present a load contain capacitance and resistance. So when output of a gate driving other gates, the output has to drive capacitive and resistive loads.