The schematic diagram of the mini telegraph key is very easy.
The core of this device is ATTiny13 microcontroller.
It forms an output signal with a ratio of 1:3, adjusts the transmission speed in a wide speed range, and ensures that the self-control connected through the miniature earpiece.
The output of the Telegraph keyer is the JFET, in the collector circuit which includes the relay K1, the contacts of which are connected to the transmitter.
PCB Dimensions 50x39mm