Summary of Contents for HamGadgets Mini Keying Adapter
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Mini Keying Adapter (MINI-KA) The Mini Keying Adapter acts as a buffer between your electronic keyer or computer and certain transmitters and transceivers that require significant keying current. For applications that do not require optical isolation, the Mini-KA offers a solution low in cost and complexity.
Parts List Part Value Mini Keying Adapter printed circuit board 1N4148 diode 2N7000 MOSFET AOI516 or IRFU220 MOSFET 100 K Ω 1/4W resistor (Brown-Black-Yellow) R1, R2 6-position terminal block Assembling the Kit Always use good static prevention practices when working with static sensitive parts. This means you should wear a grounding strap when possible, or work on a static-dissipative work surface.
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It will work the other way, of course, but it might be more difficult to make connections. You might want to hold it in place with a piece of tape while soldering. Mini Keying Adapter 01/07/2016 Page 3 of 6...
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Keying Adapter with a straight key, bug, some other electronic keyer, or even a computer serial or parallel output signal. If your radio immediately starts transmitting when you connect the keyer to the Mini Keying Adapter, you’ve probably got the IN/GND wires reversed.
Theory of Operation In logic terms, the Mini Keying Adapter consists of two inverter/buffer stages. The gate of MOSFET transistor Q1 is normally held high by resistor R1, keeping Q1 turned ON (conducting). Q1 presents a low resistance to ground, keeping the gate of Q2 near ground potential.
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Schematic and PCB Diagrams Mini Keying Adapter 01/07/2016 Page 6 of 6...