A variable resistor comprises a slide (1) with an integral contact arm (3) projecting from it to form a contact with a resistance substrate, a bow-shaped coupling arm (10) with a projection (9) for engaging with teeth on a rotor (11) and a stop (1a) formed by a projecting part of the slide. The coupling arm (10) is connected to both ends of the slide (1) and when the projection (9) engages with the rotor (11) the slide (1) rotates with the latter (11). Continued rotation of the rotor (11) causes the stop (1a) on the slide (1) to contact a stop on the housing (41) and prevents further slide (1) rotation by disengaging with the resilient projection (9). Pref. the rotor is mfd. from a polyamide resin.
