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Capacitor Discharge Unit |
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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.
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.
CONSTRUCTION
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.
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PARTS LIST |
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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 |
26-12-2019