There is no simple cut and dry answer. It depends on the specific application.
Here are some of the criteria you need to consider:

1) Power consumption
2) Mains power supply vs battery operation
3) Voltage
4) Current
5) Frequency of operation
6) Other circuits and load applied
7) Availability of components
8) Cost
9) Complexity of design
10) Other options available such as microcontroller

 

Its for a home shop pulse EDM machine. This is going to be the logic to create the equal voltage pulses needed. To not fire a pulse that is under voltage at it's start or to shut a pulse down if it is shorted.

Frequency variable in the 25KHz to 25KHz range, with variable duty cycle. The logic, mosfet drivers, and stepper motor, will be powered from a computer power supply. No load to logic except for switching the mosfet drivers, that are Cmos or TTL level.

Cost, I've got so much in this now, in failed attempts, now it's me or it. And I don't give up easy.

Micro probably would be an option if I was younger, but I'm not and learning this stuff is hard enough, with out taking on another level. Thanks for your help!

 

I would not use 74LS unless it was my only option. I like 74HC, personally.

 

Thanks Ron. That, 74hc, was my next choice over the old 40xx. But I'm still in a learning mode, so I ask you guys here.

 

Thanks Ron. That, 74hc, was my next choice over the old 40xx. But I'm still in a learning mode, so I ask you guys here.

If you have a circuit that runs on >5V, and you don't need speed, 4000 series is useful.

 

I'll have both 5V and 12V DC available in the circuit. But will use the74hc for logic. Thanks again.