Simple Design of Electronic Answering Machine-EEWORLD

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The buzzer recommended here is a simple electronic circuit that can be used in any test or quiz contest. This circuit allows 4 participants, and each contestant is assigned a number. During the competition, as long as any switch is pressed, the circuit automatically locks the entrance of the other three contestants. At the same time, the specified switch number is displayed on the 7-segment LED display, and a buzzer indication sound is emitted. When the contestant presses his own switch, the corresponding output of IC1 becomes high. Now let's assume that the pressed switch is S1. Then the input I1 of IC1 becomes high potential, and the corresponding output of Q1 also becomes high. As a result, a current flows through D5 to the buzzer PZ1, which emits an indication sound. At the same time, the current flowing through D6 and D7 causes the number of contestant No. 1 to be displayed on the LED display.

Similarly, when any of the other switches (S2~S4) is pressed, the corresponding contestant number will also be displayed on the LED display and a buzzer will sound. The S5 switch is used to reset the display. The entire circuit is powered by a 9V battery.

Keywords：LED Reference address：Simple Design of Electronic Answering Machine

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