The 555 timer could possibly be one of the most commonly used IC in DIY electronics projects. You can find many circuits and applications based on 555 Timer IC that have already been designed and published in [EasyEDA open source community][1] by our users, You can simply open any free design, edit it and get ideas from these open source designs. Here we list some simple and interesting circuits projects and applications, tutorials and books for beginners and advanced engineers. With these resources you will learn how the 555 works and will have the experience to build some of the circuits below. ##Simple 555 Timer Circuits and Applications## There are many applications of 555 timers. Here as an example we will discuss 555 Timers used in Lamp Dimmer, Wiper Speed control,Timer Switch,Variable duty cycle fixed frequency 555 oscillator etc. You can open any of these circuits and edit it to you want. **1.[NE555 Astable][2]** NE555 is configured in astable (bistable) mode, due to the pin 3 of the IC is a coupled MOSFET or (if you want,it can also be a power transistor that matches the pins of the MOSFET), you can connect a bigger load such as DC motors or 12VDC bulbs to adjust the light intensity or speed of rotation by potentiometer. ![NE555 Astable][3] **2.[Lamp Dimmer using NE555][4]** This project is about simple lamp dimmer project using NE555 timer IC. PWM method is used for controlling the brightness of the lamp. This method is very power efficient and low cost compared to linear power control circuits. In PWM method the load is driven using a high frequency square wave and the duty cycle of this square wave is varied for controlling the power delivered to the load. The efficiency of this circuit was found to be 95.5% when tested in the lab. The same circuit can be also used to control the speed of DC motors. ![Lamp dimmer][5] **3.[Wiper Speed control using NE555][6]** This project is about a simple automobile wiper speed control. The speed of the automobile wiper can be adjusted using a potentiometer using this circuit. The circuit operates from 12V DC and can be fitted to any automobile operating on 12V electrical system. With slight modification, the same circuit can be made to operate on 24V systems also. ![wiper speed control][7] **4.[Timer Switch using 555 and relay][8]** A simple circuit that powers a led strip when the momentary switch is pressed, then shuts it down automatically after XX seconds. There is a potentiometer to adjust the length of the delay but I need the light to be ON for at least 30 seconds. You can change the values of capacitor C1 and resistor R1 to what you need. A 100uF capacitor and a 500K potentiometer should give an adjustable delay of near 0 seconds to 55 seconds. ![Timer switch schematic][9] **5.[Variable duty cycle fixed frequency 555 oscillator][10]** A fixed frequency variable duty cycle oscillator based on a 555 timer and using the push-pull output to drive the RC timing through two routing diodes, a pot and a series resistor to limit the min/max duty cycle to something sensible at around 9%/91%. ![Variable duty cycle fixed frequency 555 oscillator][11] ###How 555 timer works### There are three modes of output with the 555 timer – monostable, bistable, and astable. Each mode has different characteristics, and will determine how the 555 timer outputs current. The following articles well explained the three modes of the 555 timer. part 1, [555 Timer Basics – Monostable Mode][12] part 2: [555 Timer Basics – Bistable Mode][13] part 3: [555 Timer Basics – Astable Mode][14]. ![IC NE555][15] ###555 Timer Circuits Site### The [555 Timer Circuits][16] site contains lots of the electronics info you need to know about the 555 Timer. With over 80 different electronic circuits that you can build. ###Book to learn 555 Timer Circuits and Projects### If you want to learn more about the 555 timer, you should read, understand and do things on your own with 555 IC. the book [Timer, Op Amp, and Optoelectronic Circuits and Projects Book Vol. 1 By Forrest Mims][17] is a great resource to have on your bench. The book has lots of information about the 555 timer, OpAmps, and other IC’s too. ![555 Timer Book][18] [1]: https://easyeda.com/explore [2]: https://easyeda.com/Engeltronics/NE555_Astable-4V3l1xP7N [3]: https://easyeda.com/normal/NE555_Astable-3RLFWQ8OI.png [4]: https://easyeda.com/praveenthomas/Lamp_dimmer_using_NE555-zusqoKHhR [5]: https://easyeda.com/editor/20150910/55f0619490ac0.png [6]: https://easyeda.com/praveenthomas/Wiper_speed_control-dtYgasmEy [7]: https://easyeda.com/editor/20150910/55f061eb98bdd.png [8]: https://easyeda.com/MusicalBox/Timer_switch_using_555_and_relay-vZaAyw531 [9]: https://easyeda.com/normal/Timer_switch_schematic-6lf93lDVP.png [10]: https://easyeda.com/andyfierman/Variable_duty_cycle_fixed_frequency_555_oscillator-1bc9b3f6a8cf4b3c88e5f22f6780f9c6 [11]: https://easyeda.com/normal/Variable_duty_cycle_fixed_frequency_555_oscillator-cac20e037ab8498a8bab0c8d84c67bbe [12]: http://www.circuitbasics.com/555-timer-basics-monostable-mode/ [13]: http://www.circuitbasics.com/555-timer-basics-bistable-mode/ [14]: http://www.circuitbasics.com/555-timer-basics-astable-mode/ [15]: /editor/20161130/583e3b2684db1.gif [16]: http://www.555-timer-circuits.com/ [17]: http://amzn.to/2gFj3xs [18]: /editor/20161130/583e3ee6b5053.jpg