Question

An alarm is powered by 120 VAC, and the on/off state of the alarm is controlled by an EM relay. Design the interface between a computer output port and the EM relay. The dropout voltage is 3.5 V, and the coil current needs at least 100 mA. Limit the coil voltage to 6 V. Write three software functions: Alarm_Init, Alarm_On, and Alarm_Off.

Answer 1

ANSWER:

CODE:

#include<AT89x51.h>
void delay(void)
{
unsigned int i=0;
for(i=0;i<300;i++)
{
}
}
void main(void)
{
P0=0xFF;
P1=0xFF;
P2=0xFF;
P3=0xFF;
  
while(1)
{
   if(P1==0)
   P2=0xFF;
   delay();
else if(P1==1)
       P2=0x00;
else

();
}

}

5 V dc 33pF AT89C51 XTAL1 119 ALRAM 120V AC CRYSTAL <TE 18 XTAL2 PO.D/ADO PO.1/AD1 PO.2/AD2 PO.3/AD3 P0.4/AD4 P0.5/AD5 PO.8/ADO PO.7/AD7 R1 100 <TEXT> BUZZER <TEXT> 33pF <TEXT> 9RST RELAY 5V <TEXT> 120V AC PS EN ALE P2.0/A8 P2.1/A9 P2.2/A10 P2.3/A11 P2.4/A12 P2.5/A13 P2.6/A14 P2.7/A15 <TEXT EA VONO P3.D/RXD P3.1/TXD P3.2 ANTO P3.3 NT1 P3.4/10 P3.5/T1 P3.6AWR P3.7/RD AT89 C51 <TEXT>

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