DC DRIVES

Digital and Analog Drives

  I have purposely thought out these circuits to be functionally the same; in other words, the digital circuit will not have any extra abilities over the analog version of the circuit.

 Here is the analog circuit:

and here is the digital version of the circuit:

Pink Wires - The voltage here can be any value between 5 and 10 volts.

Blue Wires - The voltage here can be either 0 or 5 volts. (2 discrete voltages)

As you can see, only the digital circuit has connections that are only 1 voltage or another, where the analog circuit doesn’t. That is the only real difference between an analog or digital motor controller, and also the difference between analog and digital circuits in general.

Analog circuits - can have a range of voltages

Digital circuits - You have a choice of two voltages. It is one or the other.

Some extra notes:

I wanted to add that the electric drive control circuit/block diagrams in the above schematics, are only cable of maintaining a constant voltage across the motor. If the motor were to be loaded (receive resistance), it would still slow down. You could build either an analog or digital control circuit to deal with this problem, but I figured that the block diagram for the analog version of the circuit would be unnecessarily complicated for answering this question. I myself like simple.