FYP 2...WEEK 6..POWER SUPPLY CIRCUIT

Figure 1:power Supply circuit

                                                                     

To power up the circuit, it should use 9V-12V battery. Higher input voltage will produce more heat at LM7805 voltage regulator. Typical voltage is 12V. However, LM7805 will still generate some heat at 12V. Refer to circuit figure, the D2 is use to protect the circuit from wrong polarity supply. C1 is use to stabilize the voltage at the input side of the LM7805 voltage regulator, while the C2 is use to stabilize the voltage at the output side of the LM7805 voltage supply. L2 is a green LED to indicate the power status of the circuit. R7 is resistor to protect LED from over current that will burn the LED.

Interface RFID Reader with PIC16F877A

For this project, user has to connect the wire of RFID reader to a circuit. There are 6 output wire of RFID reader, only 4 are used in this project. Be careful when plug in the 4 wires to the circuit; connect them according to the table shown below.