[11]Lab11 11.1 OBJECTIVES After studying this unit,the student should be able to: 1.Discuss the operation of a 555 timer 2.List the pins on the timer and give an explanation of what each does. 3.Connect the 555 timer in an electronic circuit 11.2 PIN EXPLANATION The 555 timer is an eight pin inline integrated circuit(IC).This package will have a notch at one end or a dot near one pin.These identify pin #l.Once pin #1 has been identified,the other pins are numbered as shown.The following is an explanation of each pin and what it does. Vcc RESET R THRES OUT CONT5 >o0 TRIG-2 GNDI 1 8 Vcc R T TRIG > DISCH OUTI 3 6 THRES 7 DISCH RESETn 4 5 CONT GND Fig.1 555 schematic and 8-pin package[11] Lab 11 11.1 OBJECTIVES After studying this unit，the student should be able to : 1. Discuss the operation of a 555 timer 2. List the pins on the timer and give an explanation of what each does . 3. Connect the 555 timer in an electronic circuit 11.2 PIN EXPLANATION The 555 timer is an eight pin inline integrated circuit (IC). This package will have a notch at one end or a dot near one pin. These identify pin #l. Once pin #1 has been identified, the other pins are numbered as shown. The following is an explanation of each pin and what it does. R 1 1 R S RESET 4 3 OUT VCC 8 6 THRES CONT 5 2 TRIG 1 GND 7 DISCH + - + + - + T C1 C2 R R R Fig.1 555 schematic and 8-pin package