Circuit Creations
555 Timer & Oscillator Kit 103
Introduction
Welcome to the exciting world of Circuit Creations electronics kits. To assemble this kit you will
need the following basic items:
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25W to 40W soldering iron.
Rosin core flux solder.
Diagonal cutters.
Needle nose pliers.
The central component of this kit is the 555 timer chip. Over the years there have been
numerous books, articles, and websites that provide a rich source of information that describe
hundreds of applications for the 555. The Circuit Creations 555 Timer & Oscillator Kit 103 can be
configured as an audio oscillator, an LED (Light Emitting Diode) flasher, or one shot timer with the
components that have been supplied. Your imagination is the limit for what can be done with this
kit.
Circuit Assembly
The parts list for the components that are included with Kit 103 is as follows:
Designator
U1
LED1
R1, R3
R2
R4
R5
R6
C1
C2,C3
C4
R1A
PCB1
Value
555 Timer
LED
330 Ohm Resistor
250K Potentiometer
0 Ohm Resistor
10K Resistor
390 Ohm Resistor
10uF Capacitor
0.1uF Capacitor
0.01uF Capacitor
68K Resistor
K103
Assembly Features
Notch in package must match notch printed on the circuit
board or dot on top of package must be on the same side
as the square pad on the printed circuit board.
Flat side of LED and printed circuit board must match.
Orange-Orange-Brown
Black
Brown-Black-Orange
Orange-White-Brown
Make sure + capacitor is the same as + on the circuit board.
Marked with 104
Marked with 103
Blue-Gray-Orange (Alternate resistor)
The schematic shows the component connections and describes which components are installed
for the audio oscillator, LED flasher, or timer configuration. Note that there will be one extra
resistor and one extra capacitor that do not get installed and the value depends on the
configuration. It is actually OK to install both C1 and C2 capacitors if you desire but this will
slightly alter the time/frequency range of the circuit. Be sure to pay attention to the markings on
polarized components C1, U1, and LED1.
See www.circuitcreations.com for general assembly helpful hints.
555 Timer & Oscillator Kit 103
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Operation
The following steps apply for any configuration:
1) Apply a DC voltage between 5V and 15V at J1 (for example Circuit Creations LM317
Power Supply Kit 101 or a 9V battery).
For the audio configuration
A. Connect the output to an audio amplifier driving a speaker (for example Circuit Creations
LM386 Audio Amplifier Kit 102) and adjust R2 to the desired frequency.
For the LED flasher configuration
B. Observe the LED and adjust R2 for the desired flash rate.
For the timer configuration
C. Apply a negative pulse that goes from VCC to ground that is between 10uS and 0.5s
wide to the TRIG input signal. Adjust R2 to get the desired high going pulse width on the
OUT output signal.
Refer to the data sheet for the 555 timer at
http://www.circuitcreations.com/Data_Sheets_And_Manuals.html for more information about this
device. The K103 circuit board has solder pads available for connection to the TRIG (trigger),
RST (reset), OUT (output), and CTRL (control) pins of the 555 for further experimentation and
alternative circuit configurations of your own design. ENJOY!!
Schematic
555 Timer & Oscillator Kit 103
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