novel clock control

7-52 54 novel clock control In certain applications it is often necessary to gener- ate a series of clock pulses by using switches etc. For instance, when a digital clock has to be ad- justed. More often than not a digital clock has two function buttons. When one is depressed a clock fre- quency of several Hz is generated enabling the clock to be set to roughly the correct time very quickly. When, on the other hand, the second button is depressed, only one clock pulse is generated so that the clock can be set accurately. Why then two but- tons if they both appear to perform what amounts to the same function? s a matter of fact, there is no real need to have same task by only using one. Everything now de- pends on how long the button is depressed for. If the switch is held down for less than half a second, only one clock pulse will be generated. If, however, 1 A . ribed here fulfils the two buttons. The circui esent ft e contact 2 UB O IC1 N1 ... N4 = IC1 = 4093 UB=5... 15 V 0 .0,5...