1.6 Speaker

Speaker is driven by NPN transistor, 5V powered.

Tested variants:

- Magnetic transducer (small beeper used in computer motherboards), diameter 12mm, pins 6.5mm,

5V or more, min. 40 ohm. Optional 1N4148 diode (instead of R14) protects transistor.

- Speaker (any small speaker, min. 40 ohm, or use additional resistor)

- Piezo (cca 200 ohm parallel R14 resistor needed)