Technology Electronics and Control Electronics and Control The

Technology Electronics and Control

Electronics and Control The 555 timer is an 8 -Pin D. I. L. Integrated Circuit or ‘chip’ Notch Pin 1 What it looks like

Electronics and Control Operation: • Contains 25 transistors, 2 diodes and 16 resistors • Maximum operating voltage 16 V • Maximum output current 200 m. A • Best treated as a single component with required input and output INPUT PROCESS OUTPUT If you input certain signals they will be processed / controlled in a certain manner and will produce a known output.

Electronics and Control What the 555 timer is used for: • To switch on or off an output after a certain time delay i. e. Games timer, Porch light, Childs mobile, Exercise timer. • To continually switch on and off an output i. e. Hazard warning lights, Soft toy, Bicycle indicators. • As a pulse generator i. e. To provide a series of clock pulses for a counter.

Electronics and Control Digital Terminology: To use the 555 timer correctly you have to be aware of the correct terminology: • Monostable Time • Astable Time

Electronics and Control • MONOSTABLE: This is a system which has only one stable state. It can be made to change but it will always return to its original stable state. A spring operated push button switch is an example of this. Monostable circuits are used as timers and as a single pulse generator.

Electronics and Control Monostable Circuit 7

Electronics and Control Component list: R 1= 33 k(Or/Or/Or) R 2= 1 k (Br/Bl/Re) R 3= 470(Ye/Vi/Br) R 4= 470(Ye/Vi/Br) 2 No. LEDs SW 1= Toggle Switch SW 2= Tactile Switch 555 IC 3 No. Terminal Blocks Monostable PCB circuit layout:

Electronics and Control • ASTABLE: This is a system which has no stable state. It changes from one state to the other all the time. A pendulum swings from one side to the other continuously. Astable circuits are used to flash lights or sound a loudspeaker. It can act as a square wave oscillator

Electronics and Control Astable Circuit 10

Electronics and Control Component list: R 1 = 470(Ye/Vi/Br) R 2= 1 k (Br/Bl/Re) R 3= 470(Ye/Vi/Br) VR 1= 100 K SW 1= Toggle Switch C 1=10 u. F Capacitor 2 No. LEDs 555 IC With VR 1 set at 68 K flash rate = 1 per sec Astable PCB circuit layout:

Electronics and Control Components R 1=100 ohms R 2=100 ohms R 3=100 ohms R 4=2200 ohms R 5=1 K ohms VR 1=100 k C 1=10 u. F Q 1=BC 337 -16 D 1=1 N 4148 SW 1=Toggle Astable Project Board

Electronics and Control Warning signal: 4 LEDS flash simultaneously

Electronics and Control Buzzer and 4 LEDs Oscillate ON/OFF – Lorry Reversing

Electronics and Control Theme : A Safe Environment Monostable: Egg Timer : Food / Electrical safety Bath / Oven Timer Astable: Hazard / warning lights / school crossing Bicycle indicators Burglar Alarm Steep Gradiant Indicator Personal Alarm