Capacitor Discharge Unit
with DPDT Switch
in-line version
Capacitor Discharge Unit (in-line) using DPDT switch kit is available from:
Talking Electronics for $8.50 plus $6.50 postage. 
Click HERE  to buy kit.

Built and tested for $10.50 plus $6.50 postage


Note: This unit is designed to operate one point - direct connection

Talking Electronics has produced a number of Capacitor Discharge Units but this is the cheapest and combines three interesting features.
All Talking Electronics Capacitor Discharge Units have different names of numbers and they are all covered in a discussion on THIS PAGE.
It has a DPDT switch soldered directly to the end of the PC board so the whole unit can be mounted behind the control panel. It has two LEDs showing through the panel to indicate the state of the point and screw terminals on the end of the board to make wiring easy.
The circuit has been simplified from all the previous designs and it's a wonder this has not be thought-of before.   
See the diagram below to connect the PC board to the point motor. The point motor is a double-acting solenoid  and 3 wires are taken to it. The other two wires to the board come from an AC or DC supply. A 16v AC supply will produce the best and most-reliable control of the point motor and a 12v DC supply will be barely enough to switch some point motors.   
This project puts no load on your power supply and prevents the point motor burning out.
The board also has indicator LEDs to show the position of the point.

CDU In-Line  Circuit

PCB overlay and trackwork

All the components fit on the PC board and the project comes with the DPDT toggle switch. Your supply needs to be 12v - 15v AC or DC.

All the parts fit neatly on the PC board.
The electrolytics, resistors, diode and LEDs are identified on the board and the photos show how they are soldered to the board.
The screw terminals allow the board to be easily connected to your power supply via the 2-connector block.
The 3-connector block connects to the point motor.

$8.50 plus $6.50 postage. 
 HERE to buy kit

4 - 470R
2 - 4k7

8 - 470u 25v - 35v.
1 - 1N 4004 diode
1 - 3mm red LED
1 - 3mm green LED

1  -  2-Connector terminal block
1  -  3-Connector terminal block
1  -  DPDT toggle switch

1 - Capacitor Discharge Unit In-line PCB

Extras: You can get 8 x 1,000 electrolytics in place of the 8 x 470u for $4.00 extra