The modern market offers consumers set of convenient things for computation of time – hours, stop watches, timers. The last are most convenient during the work with the set time spans. They cost quite much therefore it makes sense to try to make the timer independently
- - DD3-K176ID2 decoder;
- - DD2-K176IE13 counter;
- - relay;
- - DD1-K176IE18 generator.
1. It is possible to assemble the timer by means of three specialized chips, namely the DD3-K176ID2 decoder, the DD2-K176IE13 counter and the DD1-K176IE18 generator. The last chip is developed directly for application in the electronic clock. It contains the generator which is calculated on collaboration with the external quartz resonator, which frequency of 32,768 Hz, and frequency divider in number of two pieces at which the coefficient of division makes 215=32768 and 60.
2. This chip is equipped with the special shaper of sound signal. At the time of giving of impulse which has positive polarity on HS entrance from the exit of this chip of the same name on conclusion there are packs of the negative impulses having the frequency of filling of 2048 Hz and porosity 2. The period of filling is one second, and duration of packs – half of second. Exit of Q3 has "open" drain. And it in turn gives the chance to connect emitters which resistance more than fifty Ohms, at the same time without using emitter followers.
3. Counters of hours and minutes, chains of inclusion of sound signal and comparison, the register of memory of the alarm clock and also chain which form signals of digits in the binary code at dynamic indication are part of chip of DD2. As soon as power supply, the register of memory is given and also counters of hours and minutes are transferred automatically to zero state. To coordinate among themselves chips of K176IE13 and K176IE18 and the indicator, apply the keys which are available on VT1-VT4 transistors and the DD3 decoder.
4. Now several words about the decoder. This integrated chip is equipped with the signal converter of the binary-coded decimal code which is capable to transform them to signals of control of seven-segment indicators. Also this chip contains the triggers capable to remember signals of the entrance code. In addition it includes three operating entrances and four indicator entrances for giving of signals.
5. The decoder, the counter and the generator are powered from the GB1 battery. The current consumed from this battery does not exceed indicator in 0.35 mA.
6. After the timer is assembled, precisely establish the frequency of the setting generator. In the assembled device the quartz RVCh-72 resonator is used, but it is possible to use and any other. The main thing that it has been calculated on the frequency of 32,768 Hz. The relay in this case is used by RES49, but also it can be replaced any other small-sized with operation current 10-15 mA. Tension at the same time has to be from six to nine volts.