CODE PRACTICE OSCILLATOR KIT Ramsey Electronics Model No. CPO3 Ever wanted to hone your code skill but didn’t have an easy way to practice? This handy little kit will allow you to tap away anywhere you happen to be! Small enough to fit into your pocket or briefcase, you can take it anywhere. You’ll find yourself up to speed in no time! Great starter kit Ideal for Boy Scouts Perfect first electronic kit for schools Increase your code speed . . . practice anywhere. Easy one evening assembly CPO3 1

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PARTIAL LIST OF AVAILABLE KITS RAMSEY TRANSMITTER KITS • FM10A FM Stereo Transmitter • FM25B Synthesized FM Stereo Transmitter • AM25 Synthesized AM Transmitter • AM1 AM Transmitter RAMSEY RECEIVER KITS • FR1 FM Broadcast Receiver • AR1 Aircraft Band Receiver • AA7 Active Antenna • SC1 Shortwave Converter RAMSEY HOBBY KITS • SG7 Personal Speed Radar • SS70 Speech Scrambler • TT1 Telephone Recorder • SP1 Speakerphone • MD3 Microwave Motion Detector • PH10 Peak hold Meter • LC1 Inductance-Capacitance Meter RAMSEY AMATEUR RADIO KITS • DDF1 Doppler Direction Finder Kit • HR Series HF All Mode Receivers • QRP Series HF CW Transmitters • CW7 CW Keyer • QRP Power Amplifiers RAMSEY MINI-KITS Many other kits are available for hobby, school, scouts and j kits are always under development.

Write or call for our free CODE PRACTICE OSCILLATOR KIT INSTRUCTION MA Ramsey Electronics publication No. MCPO3 Revi First printing: January 2001 COPYRIGHT 1994 by Ramsey Electronics, Inc. 590 Fishers Station Driv 14564. All rights reserved. No portion of this publication may be copied or written permission of Ramsey Electronics, Inc. Printed in the United State CPO3 • 2

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Ramsey Publication No. MCPO3 Manual Price Only $5.00 INSTRUCTION MANUAL FOR CODE PRACTICE OSCILLATOR KIT TABLE OF CONTENTS Introduction .................................... 4 Circuit Description .......................... 4 Schematic Diagram ........................ 5 Parts Layout Diagram .................... 5 Parts List ........................................ 6 Identifying Kit Parts ........................ 7 International Morse Code ............... 8 Assembly Instructions .................. 12 Testing ......................................... 14 Conclusion ................................... 14 Ramsey Kit Warranty ................... 15 RAMSEY ELECTRONICS, INC.

590 Fishers Station Drive Victor, New York 14564 Phone (585) 924-4560 Fax (585) 924-4555 www.ramseyelectronics.com CPO3 • 3

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INTRODUCTION Morse Code has been used since 1837. It was originally used for telegraph communications and was the first method used for radio communications. For many years, Morse Code was required knowledge for any shipboard radio operator. In 1910, the Titanic was the first ship to use the international distress call SOS. Until recently, code proficiency was required for all amateur radio licensees and was even required by the Boy Scouts. It still is required for the Signaling merit badge. The CPO3 is a fun, educational kit for any skill level builder and can be used to introduce anyone to this historic means of communication.

CIRCUIT DESCRIPTION As the key is pressed, providing the circuit a ground path and starting the cycle, two things happen. C1 starts to charge via R1, R3 and R4. At this time the output of pin 3 is high. When the voltage on C1 reaches 2/3 of the supply voltage, the output of pin 3 will go low and pin 7 is grounded, starting the discharge cycle. The capacitor is discharged through R1. When the voltage on C1 reaches 1/3 of the supply voltage, the output at pin 3 goes high and pin 7 is no longer at ground. This starts the charging cycle again. Timing is completely independent of the supply voltage used. It is determined by the values R1, R3, R4 and C1.

The formula for the total time (T) of a complete cycle is: T = 0.693[(R3+R4+2R1)C1]. The component values provided allow a range of 1300 Hz to 1700 Hz. The key is attached to pin 1 and provides the kit with a ground connection, completing the circuit and turning the entire unit on. The key is basically an on/off switch. Capacitor C2 filters out noise and R2 is a current limiting resistor for the speaker, SP1. CPO3 • 4

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