Nottingham Hackspace – 555 Timer Workshop What we'll be doing RC circuits 555 Monostable circuit 555 Astable circuit “Advanced” circuits RC circuits: these basic circuits are how basic timing is done in many applications. e.g. microcontrollers often have onboard RC timer as their main clock. Monostable: one stable state Astable: no stable states Advanced circuits (if we have time!) Nottingham Hackspace – 555 Timer Workshop

Nottingham Hackspace – 555 Timer Workshop RC Circuits Capacitors can store charge. Think of them as temporary batteries. Breadboard + scope demo Nottingham Hackspace – 555 Timer Workshop

Nottingham Hackspace – 555 Timer Workshop 555 Timer Pins Nottingham Hackspace – 555 Timer Workshop

Nottingham Hackspace – 555 Timer Workshop 555 Timer “Rules” Output Discharge Trigger below 1/3 Vcc ON (Vcc) Floating (unconnected) Threshold above 2/3 Vcc Ground Nottingham Hackspace – 555 Timer Workshop

Nottingham Hackspace – 555 Timer Workshop Monostable Circuits Monostable – one permanent state. Nottingham Hackspace – 555 Timer Workshop

Nottingham Hackspace – 555 Timer Workshop Monostable Circuits Nottingham Hackspace – 555 Timer Workshop

Useful monostable equations: Time on = Monostable Circuits Useful monostable equations: Time on = 1.1𝑅𝐶 Nottingham Hackspace – 555 Timer Workshop

Nottingham Hackspace – 555 Timer Workshop Astable Circuits Astable – no permanent states. Nottingham Hackspace – 555 Timer Workshop

Nottingham Hackspace – 555 Timer Workshop Astable Circuits Nottingham Hackspace – 555 Timer Workshop

Useful astable equations: Frequency = Duty Cycle = Astable Circuits Useful astable equations: Frequency = Duty Cycle = 1.44 𝑅 1 +2 𝑅 2 𝐶 𝑅 1 + 𝑅 2 𝑅 1 +2 𝑅 2 Nottingham Hackspace – 555 Timer Workshop

Nottingham Hackspace – 555 Timer Workshop “Advanced” Circuits Astable – low duty cycle Nottingham Hackspace – 555 Timer Workshop

Nottingham Hackspace – 555 Timer Workshop “Advanced” Circuits Nottingham Hackspace – 555 Timer Workshop

More “Advanced” Circuits Voltage Controlled Oscillator (VCO) Pulse Width Modulation (PWM) Google it! Nottingham Hackspace – 555 Timer Workshop

Nottingham Hackspace – 555 Timer Workshop Schematic and breadboard images produced using Fritzing: fritzing.org This work is licensed under a Creative Commons Attribution 3.0 Unported License. Original author: James Fowkes (Twitter: @fowkc) Nottingham Hackspace – 555 Timer Workshop