DCC LIVE FROG POLARITY TESTER This was a useful little circuit that I made to enable me to check the polarity of live frog points. The circuit is extremely simple and the components are not critical. For instance any silicon diode will do for D1 and D2. The values of R1 and R2 will be suitable for most DCC systems but again are not critical. The photo below shows my prototype board in use. The circuit is identical to that shown above but the stripboard layout is slightly different from that shown on the left. N.B. On the LEDs pin 1 (the cathode – (short leg)) is shown as the pin with a square outline on the stripboard layout. Operation: When initially connected to the track both LEDs should illuminate. When the frog is probed the LED that remains brightly illuminated indicates which track is connected to the frog.
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DCC LIVE FROG POLARITY TESTER
This was a useful little circuit that I made to enable me to check the polarity of live frog points.The circuit is extremely simple and the components are not critical. For instance any silicon diode will do for D1 and D2. The values of R1 and R2 will be suitable for most DCC systems but again are not critical.
The photo below shows my prototype board in use. The circuit is identical to that shown above but the stripboard layout is slightly different from that shown on the left. N.B. On the LEDs pin 1 (the cathode – (short leg)) is shown as the pin with a square outline on the stripboard layout.
Operation: When initially connected to the track both LEDs should illuminate. When the frog is probed the LED that remains brightly illuminated indicates which track is connected to the frog.
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