The PACE TR-20 was the teaching model for analogue computing as it was a perfect representative of the range of transistorised desktop computers available in the 1960's. ?Introduction to Analog Computation' references the TR-20 as typical of its type of small desk top computers built by various manufacturers.
This model was used by the Electrical Engineering Department of the University of Technology Sydney (then the NSW Institute of Technology), to train engineers in the use of analogue computational engines. Students learnt to solve engineering problems, particularly in relation to electrical engineering.
Analogue computing had significant application well into the late 1970's. An analogue computer can model various properties as exhibited by real world events. It does not perform calculations through serial calculations as a digital computer would. The TR-20 performs the required operations in a parallel manner on continuous variables (using DC voltages).
Prior to this type of system students would have performed the necessary calculations on slide rules or large mainframe computers (when and where available). This type of system became obsolete when programmable electronic calculators offered the facilities to perform the same "calculations".
Nina Earl, Assistant Curator, 2017