Large Scale Central

Request for Sound R/C info

Electronics Power and Sound
#21

The chuff activation circuit Doug and I used was taken from Tony’s web site. The components are a 2N2222 or equivalent transistor, and a 0.1uf capacitor. Doug purchased the transistor locally from Active Electronics.

(http://ovgrs.editme.com/files/P8SoundK27/TandC.jpg)

The 2N2222 transistor has three leads called the emitter, base, and collector. The emitter on this transistor is marked with small metal tab on the edge of the transistor. The base is the center lead, and the collector the remaining one.

(http://ovgrs.editme.com/files/P8SoundK27/BoardT.jpg)

The capacitor was soldered across the traces of the circuit board for the emitter and base. The orange wire from the P8 sound board (C2:2) is for the chuff. It is connected to the collector. The orange wire from the K27 solder pad (J1:5) is for the optical sensors. It is connected to the base. The black wire from the K27 solder pad (J1:5) is a ground. It is connected to the emitter.

(http://ovgrs.editme.com/files/P8SoundK27/ChuffWires.jpg)

The other devices on the board are a transistor and resistor for the sound volume control.

#22

Paul,

Your bottom graphic clears up a question I had with your board. Not that I understand the transistor, what is the cap for? is it just to eliminate spikes that might be interpreted as a trigger signal? Tony shows the same transistor mounted directly to the main board in the K without the cap.

Bob C.

#23

Thanks a bunch Paul for doing the figuring for me. Looking at your article I had it pretty much figured out, but your little diagram above solved any issues I might have.

#24

Bob.
Just using the transistor on its own did not work reliably. The cap is also needed to smooth out the chuff timer voltage. My diagram and pics show both fitted to the Bachmann K27 socket pcb.