555 Holiday Fun Purdue University College of Liberal Arts

555 Holiday Fun Purdue University College Of Liberal Arts-Free PDF

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1 Start Concepts Conventions Components,A Concepts and conventions. All our circuits use DC electricity a battery or wall adapter do not connect them. to AC i e outlet electricity, For all our circuits we assume that the flow of electrons is in one direction only. from positive to negative The flow of electrons is called current. As a convention positive power is marked with red negative or ground GND is. marked with black or blue, We distinguish between voltage V or E potential energy pressure of electrons. into the circuit and current I amount of electrons passing a point in the circuit. look at water analogy, We distinguish between polarized and non polarized parts electric components. The orientation of a non polarized part in a circuit does not matter it does matter. however for a polarized part,555 Holiday Fun p 2,B Components.
LEDs polarized light up when electrons pass through them. Resistors non polarized limit amount of electrons that pass through them. Resistor color chart use this table to determine a resistor s value based on it s. colored rings,555 Holiday Fun p 3, Capacitors polarized non polarized store electrons after charging release. electrons when discharging do not allow any more electrons to pass once charged. longer leg is band around non polarized,cylinder specifies or GND. Transistors polarized amplify amount of electrons going through a circuit a. weak current i e few electrons controls a larger current lots of electrons. The presence absence of a current at the transistor s base determines the opening. closing of the collector emitter gate for amplification. The following picture from my old electronics junior project book illustrates this. 555 Holiday Fun p 4, ICs integrated circuit look up datasheet for polarity and pin out specialized. components that do a variety of things in case of the 555 timer IC creating a pulse. or frequency, Pins are counted counter clockwise from left of notch sometimes there s a little. dot next to pin 1,C Building Tips, How to use the breadboard look at the picture below to see how rows and columns.
connect parts on the breadboard, Keep all your jumper cables component legs etc short straight and as close as. possible to the surface of the breadboard, Use the hot foam cutter on a medium heat setting and use the special UHU glue to. stick Styrofoam pieces together, We probably won t make it to this stage in today s workshop but when soldering. parts together use the IC sockets for soldering first and then place the IC into the. socket after soldering all the connections to avoid overheating the IC. 555 Holiday Fun p 5,2 Making Things Blink part 1 lighting up an LED. Use this circuit to light up an LED Observe the LEDs polarity and use the formula below to. determine the resistance of R1 resistor 1 Look at the colored bands around the resistor. to specify its value see resistor color codes in 1 B components section. The formula next to resistor R on the left helps you to determine the correct resistor value. for R so you don t burn the LED As a rule of thumb you can use 1 7V 20mA for. standard LEDs colored i e non clear plastic cap Here is what this should look like on. your breadboard use a 470 resistor with a standard LED. The red green and,yellow LEDs in the,holiday kit are.
The blue LED is, If you would like to connect more than just one LED you can connect multiple LEDs in. series or parallel and the value of the resistor changes like this. Series circuit,LED1 LED2 LED3 1 7V 20mA,E number of LEDs x 1 7 x 1000. 9V 3 x 1 7 x 1000,555 Holiday Fun p 6, It is hard to find a 195 resistor also the values of resistors tend to vary up to 10. 20 so a safe and easy to find value for R would be 220 or 270. Parallel circuit,LED1 LED2 LED3 1 7V 20mA,E 1 7 x 1000. number of LEDs x 20 mA,9V 1 7 x 1000, Again 121 is an odd value for a resistor Also including possible imprecision R 150.
would be a safe choice, Things to think about Why do you choose a specific LED color And what ideas can the. brightness of the LED convey, If you open and close the circuit with a jumper wire the LED blinks not much fun yet so. we continue,555 Holiday Fun p 7,3 Making Things Blink part 2 the 555 Timer IC. The first circuit for making an LED blink is based on an extremely popular integrated. circuit IC called 555 timer IC This IC is extremely useful and versatile and with only a. handful of external components it can be easily configured to perform many different. timing task The main two configurations independent of the 555 s final usage are the. monostable mode one shot output and astable mode pulsed output In the following. example we use the 555 timer IC in its astable mode constantly turning an LED. connected to its output pin ON and OFF before we start building the circuit let s take a. look at the 555 s pin configuration,Here is a simple circuit for making an LED blink. 555 Holiday Fun p 8, We measure the turning on and off of the 555 timer s IC output on pin 3 in a unit called.
Hertz Hz this unit of frequency defines the number of cycles per second of a periodic. phenomenon like this, We can calculate the on off times of a 555 timer s output very precisely using this. Here is what it looks like on the breadboard, Things to think about Which ideas can be expressed using different blinking. frequencies slow fast how do they relate to reference things we know from the world. around us e g flashing lights on a police car heartbeat pulse monitor the blinking of. fireflies etc What shapes could hold such a blinking light Rudolph s nose etc. You can experiment further by connecting the output of one timer IC pin 3 to the input of. another pin 4 for more seemingly randomized flickering behavior. 555 Holiday Fun p 9,4 Making Things Pulse, This is a simple circuit I found online at http www 555 timer circuits com up down. fading led html, You might need to experiment with different values for R1 and C1 to get the desired pulse. frequency Look at section 1 B Components Transistors p 4 for a pinout of the BC547. NPN transistor,Here is the breadboard view,555 Holiday Fun p 10.
This is a more complicated circuit that also fades the LED however it uses the 555 timer. IC more closely to how we had set it up in section 3. You might have to experiment with the initial values for R1 R2 and C1 a little to make the. 555 frequency slow enough so that you can see the fading in and out of the LED or in. turn fiddle with R3 R5 and C3 for the timing of the fading processes. This is the pinout for the two 2N2222 NPN transistors in this circuit. 555 Holiday Fun p 11, 5 Making Things Blink part3 counting with the CD4017B IC. The CD4017B is a decade 1 to 10 counter IC advances its count as the clock input. becomes high e g clock or timing input from the pulsed output of a 555 timer IC Each. DECODED OUTPUT 0 9 goes high in turn as counting advances. The reset input should be low GND 0V for normal operation counting 0 9 When high it. resets the count to zero DECODED OUTPUT 0 high This can be done manually with a switch. between reset and Vs and a 10k resistor between reset and 0V Counting to less than 9. is achieved by connecting the relevant output DECODED OUTPUT 0 9 to reset for example. to count 0 1 2 3 connect DECODED OUTPUT 4 to reset. The CLOCK ENABLE input should be low GND 0V for normal operation When high it. disables counting so that clock pulses are ignored and the count is kept constant. The 10 output is high for counts 0 4 and low for 5 9 so it provides an output at 1 10 of. the clock frequency It can be used to drive the clock input of another 4017 to count the. tens since the clock input is triggered on the rising edge of a signal becoming high. This is what happens at each of the pins precisely. 555 Holiday Fun p 12, The following circuit lights up 9 LEDs in sequence the duration at which each LED is on. and the speed at which they are changing can be set with R1 R2 and C1. 6 Further Reading and experimentation, Purdue Program in Electronic and Time Based Art Website more electronics workshops. in the website s resources section, http www cla purdue edu vpa etb resources tech workshops html. For more information on the 555 timer IC see, Hewes John The Electronics Club http www kpsec freeuk com 555timer htm.
For more counting fun with LEDs see the 4026 decade counter and 7 segment display see. Hewes John The Electronics Club,http electronicsclub info cmos htm 4026. Ideas Evil Mad Scientist LED Hanukkah Menorah Kit, http www evilmadscientist com 2009 new led hanukkah menorah kit. Please e mail any feedback ideas for improvement or modifications to this document to. fwinkler purdue edu,555 Holiday Fun p 13,7 Appendix. Parts in the 555 Holiday Fun Kit,1x 330 for blue LEDs. 2x 470 for green red yellow LEDs,1x LED blue 3 4V 20mA.
1x LED red green and yellow 1 7V 20mA,1x 9V battery clip. 1x 9V battery,2x 555 timer IC,1x decade counter CD4017. 1x 16pin DIP socket,Capacitors,1x 0 001 F,Transistors. 1x breadboard, Hookup wires solid core and stranded solder soldering equipment Styrofoam and a. Styrofoam cutter and UHU Styrofoam glue are available in the ETB lab. The website for a download of this document is, http www cla purdue edu vpa etb events 555 workshop handout pdf.
555 Holiday Fun p 11 This is a more complicated circuit that also fades the LED however it uses the 555 timer IC more closely to how we had set it up in section 3 You might have to experiment with the initial values for R1 R2 and C1 a little to make the 555 frequency slow enough so that you can see the fading in and out of the LED or in

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