Inexpensive Analog Computer A small analog computer, suitable for instructional use, wes built far under $450, including $170 for nine operat i a n d anplifiers (OAs) and a multiplier/divider, and 8100 far a large supply of small parts from state surplus property. The instrument consists of a main power supply which provides 0.3 amp a t *lS V, an assembly of five OAs and multiplier/divider with terminal access providing easy component plug-in (dual banana plugs) and interconnection, R. meter circuit with full-scale sensitivity from 0.6 mV to 300 V and with input switching to all pertinent points in the instrument, two adjustable precision voltage sources, two precision ten-turn potentiometers, and a. signal generator with square- and triangular-wave outputs a t frequencies from 0.005 to 20 Hz, operable either monostably or free-running. Components are assembled on three panels, mounted on a standard relay rack. The instrument has nroven auite satisfactorv for student exoerimentation with elementarv OA circuits snd for thr n m l o ~ i n ~ h t i o 01 n ~ i u q d cproI>Im~.III I\lne!w. H- pre'~~lhrcIIn ..cmr phv-IC-1~ h t w ~ i - t rtexli. v .\l.n, i t 1):~sI,wrc n~wd:aa o Ion runrut rnr h o c ~ r r powr>tio.tnt for ~ l r v ~ l c , ~ . ~ t uf r ~ryclir ~ t i o ~wl[unmetr\ ~3nol chror.
