Save 50 - 555 Circuits
(more than 101
Circuits) as:
.doc (5.8MB) or .pdf (5.6MB)
(8-6-2023)
(This eBook is being updated all the time and
the .doc and .pdf will NOT contain the latest additions)
For our other free eBooks,
Go to: 1 -
100 Transistor Circuits
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For more data on the 555, see these pages:
555-Page 1
for CD users:
555-Page 1
555-Page 2
555-Page 2
555-Page 3
555-Page 3
555-Test
555-Test
To learn about the development and history of the
555, go to these links:
http://semiconductormuseum.com/Museum_Index.htm - a general discussion
about the development of the transistor
http://semiconductormuseum.com/Transistors/LectureHall/Camenzind/Camenzind_Index.htm
- history of the 555 - Page1
http://www.semiconductormuseum.com/Transistors/LectureHall/Camenzind/Camenzind_Page2.htm
- history of the 555 - Page2
http://www.semiconductormuseum.com/Transistors/LectureHall/Camenzind/Camenzind_Page3.htm
- history of the 555 - Page3
http://www.semiconductormuseum.com/Transistors/LectureHall/Camenzind/Camenzind_Page4.htm
- history of the 555 - Page4
http://www.semiconductormuseum.com/Transistors/LectureHall/Camenzind/Camenzind_Page5.htm
- history of the 555 - Page5
http://www.semiconductormuseum.com/Transistors/LectureHall/Camenzind/Camenzind_Page6.htm
- history of the 555 - Page6
http://www.semiconductormuseum.com/Transistors/LectureHall/Camenzind/Camenzind_Page7.htm
- history of the 555 - Page7
http://www.semiconductormuseum.com/Transistors/LectureHall/Camenzind/Camenzind_Page8.htm
- history of the 555 - Page8
http://www.semiconductormuseum.com/Transistors/LectureHall/Camenzind/Camenzind_Page9.htm
- history of the 555 - Page9
http://www.semiconductormuseum.com/Transistors/LectureHall/Camenzind/Camenzind_Page10.htm
- history of the 555 - Page10
For a list of every electronic symbol, see:
Circuit Symbols.
For more articles and projects for the hobbyist: see TALKING ELECTRONICS WEBSITE
See TALKING ELECTRONICS WEBSITE
email Colin Mitchell:
talking@tpg.com.au
This set of 555 projects has increased to the largest on the web, with many
circuits designed by me as a request
from readers. The whole site has been copied by many other sites without any
reference or acknowledgement to
me. But you can see the circuits are mine by the way they have been drawn and
none of the other sites keep
updating with the latest additions.
Over one million readers have viewed this article and many have saved it as
.pdf
This is the only site that teaches you how to learn and remember how a 555 works
and this is very important
when you want to design a new circuit. The secret is: you can hold
the 555 with the output LOW by putting
a high on pin 6, but when pin 2 goes LOW, the output goes HIGH. Pin 2 dominates
over pin 6.
WHAT IS THE 555? The 555 is an 8-pin chip that can be turned into lots of different things (building blocks). The circuit inside the 555 is just an amplifier with 2 inputs and an output. The parts you add to the chip determine the final result (effect). In most cases you add a capacitor and resistor to produce a circuit known as a TIME DELAY CIRCUIT and the chip has a detection-pin and an amplifier (also called a power amplifier) to produce an output. It is not just a "timer," "delay" or "oscillator" but is capable of being converted into these and maybe 100 other circuits. Just call it the "555"
The 555 HOW IT WORKS
The 555 takes 10mA ALL THE TIME . . . even when the output is LOW INTRODUCTION This e-book covers the 555. The 555 is everywhere and it is one of the cheapest and most-rugged chips on the market. It comes as a TTL 555 and will operate from 4v to about 16-18v. (but don't use less than 5.5v) It costs from 10 cents (eBay) to $1.20 depending on the quantity and distributor. The circuitry inside the chip takes about 10mA - even when the output is not driving a load. This means it is not suitable for battery operation if the chip is to be powered ALL THE TIME. The 555 is also available as a CMOS chip (ICM7555 or ICL7555 or TLC555) and will operate from 2v to 18v and takes 60uA when the circuitry inside the chip is powered. The "7555" costs from 60 cents (eBay) to $2.00. But the output driving capability is a lot less than the TTL 555. We call the TTL version "555" and the CMOS version "7555." This is called ELECTRONICS JARGON. The 555 comes as a single timer in an 8-pin package or a dual timer (556) in a 14 pin package. The 7555 comes as a single timer in an 8-pin package or a dual timer (7556) in a 14 pin package. The 555 and 7555 are called TIMERS or Timer Chips. They contain about 28 transistors and the only extra components you need are called TIMING COMPONENTS. This is an external resistor and capacitor. When a capacitor is connected to a voltage, it takes a period of time to charge. If a resistor is placed in series with the capacitor, the timing will increase. The chip detects the rising and falling voltage on the capacitor. When the voltage on the capacitor is 2/3 of the supply the output goes LOW and when the voltage falls to 1/3, the output goes HIGH. We can also do other things with the chip such as "freezing" or halting its operation, or allowing it to produce a single HIGH-LOW on the output pin. This is called a "ONE-SHOT" or MONOSTABLE OPERATION - but it still takes 10mA while "sitting around". When the chip produces an output frequency above 1 cycle per second, (1Hz), the circuit is called an OSCILLATOR and below one cycle per second, it is called a TIMER. But the chip should not be called a "555 Timer," as it has so many applications. That's why we call it a "555." (triple 5) Another thing you have to be aware of is the voltage on output pin 3. It is about 1-2v LESS THAN rail voltage and does not go to 0v (about 0.7v for 10mA- output - and up to 1900mV for 200mA sinking current). For instance, to get an output swing of 10v you will need a 12.6v supply. In "electronic terms" the 555 has very poor sinking and sourcing capabilities. One way to understand how the chip operates is to remember that pin 7 goes LOW when pin 3 (the output pin) goes LOW. When pin 3 goes HIGH, pin 7 goes "open circuit" (it does not go HIGH - it goes HIGH IMPEDANCE). When pin 4 is taken LOW, (it needs to be as low as 0.5v) the chip stops operating, but it still takes 10mA. For photos of nearly every electronic component, see this website: https://www.egr.msu.edu/eceshop/Parts_Inventory/totalinventory.php You can also search the web for videos showing the 555 in action. Here are a few: Making A 555 LED Flasher – Video Tutorial Three 555 LED Flasher 555 Timer Flasher Fading LED with 555 timer Each website has lots more videos and you can see exactly how the circuits work. But there is nothing like building the circuit and that's why you need to re-enforce your knowledge by ACTUAL CONSTRUCTION. Learning Electronics is like building a model with Lego bricks. Each "topic" or "subject" or "area" must be covered fully and perfectly, just like a Lego brick is perfect and fits with interference-fit to the next block. When you complete this eBook, you can safely say you will have mastered the 555 - one more "building block" under your belt and in the process you learn about DC motors, Stepper motors, servos, 4017 chips, LEDs and lots of other things. Any one of these can take you off in a completely different direction. So, lets start . . .
Colin Mitchell
To save space (and get everything on a single page) we have not provided lengthy explanations of how any of the
circuits work. This has already been covered in TALKING ELECTRONICS
Basic Electronics Course, and can be obtained on a
CD for $10.00
(posted
to anywhere in the world). See Talking Electronics website (http://www.talkingelectronics.com) for more
details on the 555 by clicking on the following
four pages:
555-Page 1
555-Page 2
555-Page 3
555-Test
SI NOTATION All the schematics in this eBook have components that are labelled using the System International (SI) notation system. The SI system is an easy way to show values without the need for a decimal point. Sometimes the decimal point is difficult to see and the SI system overcomes this problem and offers a clear advantage. Resistor values are in ohms (R), and the multipliers are: k for kilo, M for Mega. Capacitance is measured in farads (F) and the sub-multiples are u for micro, n for nano, and p for pico. Inductors are measured in Henrys (H) and the sub-multiples are mH for milliHenry and uH for microHenry. A 10 ohm resistor would be written as 10R and a 0.001u capacitor as 1n. The markings on components are written slightly differently to the way they are shown on a circuit diagram (such as 100p on a circuit and 101 on the capacitor or 10 on a capacitor and 10p on a diagram) and you will have to look on the internet under Basic Electronics to learn about these differences. Here's a 555 built from transistors by Eric Schlaepfer in honor of Hans Camenzined, who invented the 555:
NEW!
FROM TALKING
ELECTRONICS Here is another 555 calculator by Jeff:
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There
are 5 different sizes and you will need to find out the
"foot-print" before making a Printed Circuit board. 
