You can drop all off the transistors and resistors if your motors don’t drain too much current. You only need a 74F139 or 74S139 NOT the LS version. The chip can provide peak currents up to 100mA for a short time (<1 second) and to one output at a time. This is for normal connections. I don’t know how far you can go with this misbehavior. It’s nothing special, but you get the idea how it is done.
Read More Source:
http://library.solarbotics.net/circuits/driver_zoelen.html
This entry was posted on Thursday, October 16th, 2008 at 7:20 am and is filed under motor speed controller.
