(57) A potentiometer, particularly suitable for use in automotive engine management systems,
comprises a film resistance track (1) on a substrate (2) and terminals (10, 11) for
connection to a voltage source. A wiper (3, 7) traverses the track (1) and a conductive
collector (8) which is connected to a terminal (6) at which an output voltage is obtained.
A film resistor network (9A, 9B) is provided at one or both ends of the track (1)
in series with the track (1) and the terminals (10, 11), or in parallel with a portion
(1A) of the track(1) at one or both ends thereof. The networks (9A, 9B) comprise interconnected
resistance elements formed by application of conductive film links (14A, 14B) to a
single film resistance element (12A, 12B), the links (14A, 14B) being selectively
severable to allow adjustment, to a predetermined value, of the resistance of the
network(s) (9A, 9B) in series with the track (1) or in parallel with the portion (1A)
of the track (1). The networks (9A, 9B) allow the output voltage characteristics of
the potentiometer with respect to the wiper position, to be adjusted.
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