Programmable windscreen-wiper switch for vehicle - has comparator, counters and selection circuit allowing various modes

摘要

The switch has a counter (4) driven by an oscillator (1) via a selection circuit (2). A comparator (6) compares the contents of this counter with those of a second counter (5) selected by the selection circuit. The selection circuit position is controlled by control logic (3). The outputs of the comparator and the control logic are connected to a pulse output circuit (7). The selection circuit may be a part of the counters or it may be separate from them. The control logic has control inputs (a-c) for inputting start, repeat, reset and continuous wiping signals. The oscillator is controlled by an electronic tachometer (1a) and a moisture detector (1b).