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Automatic Dual Output Display Circuit Principle

2016-12-08 05:55  
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Here we introduce to you operating principle of this circuit: this circuit lights up ten bulbs sequentially, first in one direc determined and then in the opposite direction, thus giving a nice visual effect. In this circuit, gates N1 and N2 form an oscillator. The output of the oscillator as a clock for BCD up / down counter CD4510 (IC2). According to the logic state at its pin 10, the counter counts up or down. After a few operations, pin 7 is an active low pulse IC2 output reaches the ninth count. Similarly, in the countdown operation, you have to get a pulse on pin 7 will be low. The terminal count output from the pin 7, by means of the inversion gate N3 is connected to the clock pin 14 of decade counter IC3 (CD4017 ) configured here as a toggle switch trigger output by returning to its second quarter to the RESET pin of the pin 4 15. Therefore, the output at pin 3 of IC3 to logic 1 and logic 0 state alternately at each terminal count of IC2. Initially, pin 3 (Q0) IC3 high and the counter is finished in a few states. Reached number nine, pin 3 IC3 is lower, so IC2 starts counting down. When the counter reaches 0 to statistics, the output of the second quarter, IC3 instantly high, so will reset the pin 3 to logic 1 state, the cycle is repeated. BCD output of IC2 is connected to 110 decoder CD4028 (IC4). After the operation in a few IC2, IC4 output to rise by a logical sequence Q0 point, thereby triggering the triacs your school and light bulbs 1-10, one by one. Thereafter, the countdown operation, IC2 light bulb in reverse order, presenting a wonderful visual effect. This is the principle of the circuit is simple and practical.




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