Digitally set timing circuits to produce ON and OFF timing periods.



        The CT33 is a Solid-state sequential timer employing Cmos digital logic circuitry and AC triac outputs. Two digitally set timing circuits produce ON and OFF timing periods. Each period is thumbwheel settable from 00 to 99 in single digit steps and each can be set in seconds or minutes.  All components are mounted on a single circuit board, designed for direct mounting into a standard NEMA type enclosure. The power supply is transformer isolated, has a replaceable fuse on the circuit board and power line suppression. Field wiring is connected to a six position barrier type terminal strip. Two terminals are for connecting the AC line input, two for connecting to the load circuits and two are for connecting a power ON/OFF switch.

 Optional override push-button can be mounted in the cover of the enclosure and is used to reset the OFF period and set to the ON period to energize the load on demand. Connecting terminals TA and TB are located on the left hand side of the board. The timer can be supplied with the ON period in multiples of half the  AC line period (8.33 milliseconds) instead of seconds or minutes. An ON period of 50 milliseconds would be obtained by setting the ON switches to 06 and a period of 100 milliseconds by setting the switches to 12, etc.

Two thumbwheel switches for each of the timing circuits (ON & OFF) can be changed by either turning the wheel at the bottom of the switch, or by using a screwdriver in the slot in the center of the switch. Both switches can be rotated from 0-9 in single digit steps. This gives a range of 00 to 99 in seconds or minutes, as selected by the two position switch located to the left of the ON switches (S5) and to the right of the OFF switches (S6). The timing is LINE SYNCHRONIZED and no calibration or alignment is necessary. With the OFF switches set to 00 the output will stay on.


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