A very simple but highly efficient combination lock circuit is shown in the figure. Any type of on/off switches can be used, varying from commercially available inexpensive types to more sophisticated ...

Several years ago, Paul Rako, in collaboration with the late, great Bob Pease, wrote a terrific article about the finer theoretical and practical points of electromagnetic solenoid-driver circuits. 1 ...

Several safety-critical solenoids in a laser-measurement system on an automotive-assembly line required protection from internal overheating during normal operation. After a 60-sec activation, the ...