Engineering topics
Publications and source records attributed to Cole, S. W..
Uses VMOS field-effect power transistor. High-current drive circuit employs n-channel enhancement-mode VMOS field-effect power transistor to eliminate problem of oscillation at high power encountered in conventional circuits with bipolar transistors. Drive voltage required is typically 1 to 3 V for load current of 10 A.
Instrument measures rapidly changing knee of V-I curve with extra care. Portable data logger runs on own batteries. Includes microcomputer, which controls voltage-, current-measurement increment, and solid state memory, which stores data until transferred to EPROM module. Data logger is light, compact and easily caried to remote field locations.
Electronic load circuit for displaying current/voltage characteristic curves of power sources uses low-cost low-power CMOS operational amplifiers to control load current flowing through power MOSFET Q2 and main load transistor Q3. Thermal cutoff device turns off transistor Q3 in case of overload. To maximize battery life, battery is connected via "push-to-read" momentary-contact pushbutton switch.