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JAM (just a minute) circuit schematic presentation

2017-08-15 05:22  
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This article is JAM (just a minute) circuit schematic presentation. The principle is simple but effective. For you to more effectively grasp this principle, we recommend that you read the text combines schematic. This jam circuit can be used to test any participant in the race according to his button (switch) on the other players, to get the first chance to answer a question. The circuit presented here allows up to eight participants and each assigned a different number (1 - 8). The display will show the number of players he pressed a button on others. At the same time, the buzzer will sound. Two, display and buzzer must be manually reset using a common reset switch. Initially, when the reset switch 9 is temporarily suppressed student and release, all outputs  74 ls373  (IC1) Transparent lock go "high", because all the input data line is returned to Vcc through resistor R1 through R8. All eight output is connected to the input IC1 priority encoder 74 ls147 (IC2) and 8-input NAND gate 74 ls30 (IC3). IC3's output has thus become a logic 0 after inversion through NAND gate N2, applied to lock the pin 11 IC1's. All input pins IC2 is logic 1, the output is 0000, BCD code applied to seven segment decoder / driver 74 ls47 (IC6) after the hex inverter gates reversed within 74 ls04 (IC5). Thus, resetting the display to 0. When any one push the switch "S1 to S8" is pressed, the corresponding output lines are at logic level 0 IC1 lock and display the number associated with a particular switch. At the same time, a high output leads 8, which results in an output IC3 two gates N1 and N2 to a logic 0 state. Logic 0 output of gate N2 IC1 suppressed, thereby pressing any other switches S1 to S8 has no effect. Thus, competitors according to his switch first, plugging display to show only his number. In the unlikely event while pressing (second difference in a few nanometers) of the plurality of switches, a higher priority number (switch is not.) Will be displayed. Meanwhile, a logic 0 output driver door buzzer via pnp transistor N1 BC158 (T1). Also show buzzer sound can be reset (display 0) through momentary push the reset switch 9 students may begin this next round. Lab Note: the author of the original circuit has been modified to send, because it does not jam, and higher display digital switch (higher priority), even pressure, to change the displayed number. If you are reading this first principle, the proposed Duokanjibian, grasp this principle.

JAM (Just A Minute) Circuit

JAM (Just A Minute) Circuit

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