- Published in issue 12/1992 on page 52
The stepper presented here makes use of nine positions of a 12-position rotary swtch. It is, of course, possible to add the omitted steps, As usual, the amplification factors are arrived at by connecting a number of reststors in series in the feedback circuit. The resistors used here are from the E-96 series, which enable a fairly accurate approximation of the wanted amplification. If greater preciston is required, combinations of two resistors may be used. This has the drawback, however, that a make-before-break switch must be used to prevent the output constantly being switched to the supply line.