The electronic timer can be used in engine-independent vehicle heaters which operate according to the principle of rotational atomisation, the evaporator principle and the high-pressure atomisation principle. The square-wave voltage produced by an astable generator is fed to the first input of two NAND gates which are connected in series and have two inputs and the second inputs of which are driven in each case to reach the operating state and the run-on time. An integrated circuit consisting of two 4-digit binary incrementors connected in series is connected downstream of these two gates and the output signals of the said incrementors, negated by gates, control function units of the heating devices. The signal which terminates the run-on simultaneously resets a flip-flop which, by means of its output, causes the counters to be reset and initiates a single restart. The control times can vary greatly depending on the combustion principle selected. This electronic timer ensures that the times can be freely selected independently of one another. IMAGE
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