The circuit of Figure 5-103 functions as a sequential combination lock. To operate the lock, proceed as follows:

1. Momentarily activate the RESET switch.

2. Set the switches SWA, SWB, and SWC to the first part of the combination. Then momentarily toggle the ENTER switch back and forth.

3. Set the switches to the second part of the combination, and toggle ENTER again. This should produce a HIGH at Q₂ to open the lock.

If the incorrect combination is entered in either step, the operator must start the sequence over. Analyze the circuit and determine the correct sequence of combinations that will open the lock.

Figure 5-103

Transcribed Image Text:

SWA SWB SWC +Vcc ww 5 6 ENTER O NO ONC N 7 +Voc +Vcc CLK D CLR CLR CLK Q₁ Q₂ +Vcc RESET OPEN LOCK