Hobby diy
27MHz Fm Narrow Band transmitter
NBFM or Narrow Band Frequncy Modulation is used in this 27 MHz fm transmitter circuit schematic. This circuit is an application by Motorola MC2833 - VHF transmitter with FM modulation and narrow band in a single chip.
The output power is 10mW (+10 dBm) and the coverage is 10 - 20m.
P1 is used to adjust microphone [...]
Rotative speed regulator borer, driller controller
This rotative speed regulator circuit schematic allows to control the holing speed of your borer or driller machine. This project is based on the fact that if the load grows, the voltage decrease and current increase. Use this circuit to control the speed of revolutions of your drilling mill or bench drill.
Mini audio compressor schematic
This mini audio compressor circuit use only one active component T1. The audio signal goes thru C1, R1, D1, C2, R3. Still a part of audio signal charge the D3/D4 detector and creates a control voltage for T1.
The fading time depends on C4 and R5. With an audio input variation of 50dB, the output signal [...]
