[Al Skierkiewicz]

No, it's a perfect explanation, Steve.
To take this descussion a step further, the switches in the Victor are capable of switching on and off at about 120HZ and with varying pulse width to accomplish the speed control. The Spike uses the exact same configuration except with relays. A Spike cannot control speed but it can turn on any switch which can allow both outputs to be connected to the positive voltage or the negative voltage which is handy when controlling some solenoid valves.