K3ng Keyer Schematic ((link)) Jun 2026

The solves this with a 2N2222A transistor (or BS170 MOSFET) and a 1kΩ base resistor .

The core of the K3NG keyer is an Arduino board (Arduino Uno or Mega), which serves as the "brain." The schematic is modular, meaning you can build a basic keyer or a feature-rich unit. Core Components of the Schematic

Because this device operates in close proximity to High-Frequency (HF) radio transmitters, can cause the Arduino to freeze, crash, or send random strings of dits and dahs. To bulletproof your K3NG schematic against RF:

Understanding the is the first step toward building a highly customized, feature-rich CW tool for your shack. This comprehensive guide breaks down the core circuit design, essential components, and wiring configurations required to build your own. Why Build a K3NG Keyer?

Do not connect the Arduino digital pins directly to your radio's key jack. High voltages or negative voltages from older rigs can destroy the micro-controller. k3ng keyer schematic

Connected between a digital pin (e.g., D7) and ground. Pressing this enters the configuration mode, allowing you to change settings by sending Morse code commands through the paddle.

The Morse paddle connects directly to the Arduino's digital input pins.

Which (Nano, Uno, Mega) are you planning to use?

A stereo jack connected to digital pins for left/right paddles. The solves this with a 2N2222A transistor (or

Typically uses a transistor (e.g., 2N2222) to act as a switch to key the transmitter.

Will you connect this to a or an older tube rig ? Share public link

Connected between an Arduino output pin (e.g., D13) and Ground. A small capacitor (e.g.,

This is arguably the most important part of the schematic for radio interfacing. The microcontroller’s 5V/40mA output cannot directly key most transceivers (which require a low-resistance short to ground). To bulletproof your K3NG schematic against RF: Understanding

Use an NPN transistor. The base goes to the Arduino (via a resistor), emitter to ground, and collector to the transmitter key jack.

To leverage the full power of the K3NG firmware, you can expand your schematic by wiring additional peripherals to the unused pins of your Arduino. Speed Control (Potentiometer)

If designing a PCB seems daunting, look into community-designed kits like the K5BCQ K3NG Keyer board , which lays out a robust, populated board based on the schematic. Resources for the K3NG Schematic Official Repository: K3NG GitHub Community Support: Radio Artisan Group (Groups.io)

The keyer's primary job is to control your radio transmitter: