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Easy Morse Code Keyer Circuit

For those amateurs who are planning to learn their code and upgrade, some type of on the air experience is virtually essential for the higher code speeds. This means a paddle is needed as well as some type of keying circuit to drive it. The circuit in figure 1 is based on the famous Curtis family of morse keyer chips and has a proven record of dependability. Thousands of amateurs worldwide have built some variation of this circuit and it has also found its way into many QRP rigs.

The circuit in Figure 1 consists of the 8044ABM Morse keyer chip which is readily available from Mouser Electronics. All other parts may be found at Radio Shack. Because the circuit has such a low current drain, an on/off switch isn't needed and a 9 volt battery will easily give over a year of frequent use.

PARTS LIST:

IC-1 8044ABM Morse Keyer IC. Available from Mouser Electronics, 958 North Main Street, Mansfield TX 76063-4827, Tel. 1-800-346-6873. Price is $19.95 plus shipping.
R1, R4 470 ohm watt resistor
R2, R3, R6 1 meg ohm watt resistor
R7, R9 100 kilo ohm watt resistor
R5 1 meg ohm potentiometer
R8 47 kilo ohm watt resistor
R10 1 kilo ohm watt resistor
C1 10 microfarad electrolytic capacitor, 16volt or greater
C2, C3, C5 .01 microfarad ceramic capacitor
C4 .15 microfarad ceramic capacitor (Use a .1 and a .047 in parallel)
Q1 2N2222A NPN or similar switching transistor

DE N1HFX


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