Advice on DC circuit

[JohnSmithUK]

I have been thinking, dangerous I know.

I am trying to figure out how to control the sections on my layout.

I purchased as a test the switch pictured below. In my mind it was perfect, easy to mount in a panel, and would give me a lit LED to show which section is switched on in the panel.

I now realise that as it relies on a LED it will quite happily allow movements both backwards and forwards, but the LED only comes on when going forwards.

This brings me to my question.

The very rough and ready attempt at a curcuit diagram below, would it allow me to control sections, and have a light come on, and if differing colours used, would also show the direction?

Feel free to mock my lack of electrical knowledge, and MS paint skills.

[Tricky Dicky]

Sorry to burst your bubble but I am afraid it would not work . The reason being that your controller is providing a constantly varying voltage you simply could not use fixed value resistors in those circumstances. It's the same reason why coach lights dim go off when you stop a train using DC.

The the way most people who use indicators to show the section status do it, is to use DPDT switch using one half as a SPST for the section and the other half with a separate power supply for the LED indicator. Of course this only shows the section is switched and not which direction.

I cannot see with one controller how you can end up with a section with different polarity from the rest of the layout. With two controllers yes but surely you would set both to approx. the same setting to achieve a smooth transition from one controllers section to another.

Richard

[JohnSmithUK]

Thank you.

I have had more thoughts and the direction indicator was overkill. The polarity question was to get the LED to light up, when the power is set to reverse, it is going against how the LED in the switch I tried is set up.

I have decided to do it the easy way, and some light switches are going to do the job now.

[Tricky Dicky]

Thank you.

I have had more thoughts and the direction indicator was overkill. The polarity question was to get the LED to light up, when the power is set to reverse, it is going against how the LED in the switch I tried is set up.

I have decided to do it the easy way, and some light switches are going to do the job now.

One possible way of using your existing switch/s is to indirectly switch your sections using a relay. The relay contacts can be used to switch the track feed whilst the switch is used to energise the relay coil, this will still require a separate PSU for relays but if you already have accessories running off a separate PSU you should be able to provide for the relay/s as low voltage relay switching currents are quite low.

In your original post you said the LED was coming on does the switch have a built in resistor or have had to add one to control the current?

Richard

[JohnSmithUK]

Thank you.

I have had more thoughts and the direction indicator was overkill. The polarity question was to get the LED to light up, when the power is set to reverse, it is going against how the LED in the switch I tried is set up.

I have decided to do it the easy way, and some light switches are going to do the job now.

One possible way of using your existing switch/s is to indirectly switch your sections using a relay. The relay contacts can be used to switch the track feed whilst the switch is used to energise the relay coil, this will still require a separate PSU for relays but if you already have accessories running off a separate PSU you should be able to provide for the relay/s as low voltage relay switching currents are quite low.

In your original post you said the LED was coming on does the switch have a built in resistor or have had to add one to control the current?

Richard

The LED is part of the switch. It is a Carling style rocker switch.

I only paid a pound for it, so will chalk it up to experience, and add it to my box of random spares.

It looks a bit messy, but worked fine apart from the LED only working when moving forward, no matter how slowly.