Hi,
I've made a simple program to translate user inputted plaintext to morse code by time dependant switching of a transistor. However, while the circuit and software works when having an LED as a placeholder for the keying circuit, it does not work when interfaced with a Pixie transceiver. The NPN (P2N222) transistor functions as a relay that either shorts the keying headphone jack to ground or leaves the circuit open. I'm uncertain if this is the correct way to do it Reading from my multimeter it seems the transistor doesnt switch at all, as I get a zero amp reading compared to a regular ~9v and 115 mA reading if the key is closed.
Am I missing something essential here? Again, the circuit seems to be working allright with a LED acting as a key, but not when interfaced with the Pixie. I use a 1k ohm base resistor, and set the base high and low from a digital output pin on my Uno.
Will the higher voltage in the keying circuit (9V) relative to my base (5V arduino) require me to use a PNP transistor instead?