six hour timer

K. Siol time six hour timer S1 therefore enables the operator to select a hours. As soon ass period of from one to six the transistor will selected output goes high, conducting and the relay will be deactivated (t) . e e- by switching off the radio/record player etc. As the enable input of the 4017 is also connected to the wiper of S1 any subsequent clock pulses will have no effect on the counter. The unit will there- fore remain in the "off" state until the reset button is depressed. The 4050 CMOS buffer IC and the seven LEDs have been included to give an indication of the number of hours that have actually passed. These com- ponents can, of course, be omitted if an elapsed time display is not required. The supply voltage for the circuit is not critical and may be anywhere between 5 and 15 V. The current consumption of the circuit, not including the relay, is in the order of off This control unit was originally designed to turnthat stereo equipment automatically at night, so musi...