Circuit for individual control of the autofocus motor in slide projectors

摘要

A circuit for individual control of the autofocus motor in slide projectors is described. The circuit can be operated from a remote control section of the projector, and has the effect that the autofocus circuit can be switched off and the autofocus motor can be switched on using the switch provided on the remote control section. The circuit is distinguished in that it manages without mechanical switches. For this purpose, the circuit has a flip flop which opens or closes a switch in the autofocus motor circuit of the projector. The flip flop is set in its first control state, in which the switch is closed, when the projector voltage drops during change of slide and magazine transport. Consequently, the autofocus circuit is switched on at each change of slide. The flip flop is set to its second control state, in which the switch in the autofocus circuit is open, when the autofocus motor is directly connected to the voltage by operating the focusing switch at the remote control section. During the next change of slide, the flip flop is then reset again, and thus the autofocus circuit is switched on again. <IMAGE>