Help With Model Railroad Control Panel - Electronic Circuits Projects Diagrams Free

Exit109GTI · 19th August 2005, 08:08 PM

Hey everyone, this is my first post on the site. I'm new to electronics, so I hope someone can help me.

Building a control panel for a model railroad. The railroad will be split up into a number of blocks, and the control panel will be able to turn on or off power to each block. The power will be a variable 18VDC source. For each block that is powered, I want a LED to light up on the control panel.

Here is what I have setup so far.

I have a set of mechanic switches, that when on light up a LED, and provides forward bias for a switch transitor. The transistors collector and base is then hooked up to my variable 18VDC source that drives the trains.

It's not working, even when the switch is off and the 9V battery is removed, the train is still getting power, and lots of it.

My problem I think is that the current breakover limit on my transistor is 600mA, and a N Scale locomotive draws like 1000mA. Would this cause the problem? Would I be able to wire 2+ transistors in parallel to handle more current?

Am I even doing this the right way?

Someone Electro · 19th August 2005, 08:38 PM

Why not directly switch it whith the mechanical switch.

It can probobly 1A

Exit109GTI · 19th August 2005, 08:41 PM

Quote:

Originally Posted by Someone Electro

Why not directly switch it whith the mechanical switch.

It can probobly 1A

The power source is a variable 18VDC. It can range from nothing to full on power, and I can't think of any other way to light up a LED when the 18VDC is zero, and when it's at max power.

Someone Electro · 19th August 2005, 08:44 PM

Then have an switch that closes 2 contacts at the same time.So one contact is for the train and the other for the LED.

Easy.

Exit109GTI · 19th August 2005, 08:48 PM

Quote:

Originally Posted by Someone Electro

Then have an switch that closes 2 contacts at the same time.So one contact is for the train and the other for the LED.

Easy.

I don't understand what you mean, can you be more specific?

Someone Electro · 19th August 2005, 09:11 PM

Its a single switch but it atcs as 2 switches togeter. You close the switch and its 2 switches will close and you open it an bouth switches will open.

This is manly used in mais becose you never know on wich wire is live (the live wire can only shock you!) So it disconects bouth wires to make it a litle safer.

Think it as 2 switches sharing the same button.

These kind are not as comon as single contact switches but it shod not be to hard to find.

Exo · 19th August 2005, 09:22 PM

Quote:

Originally Posted by Exit109GTI

Quote:

Originally Posted by Someone Electro

Then have an switch that closes 2 contacts at the same time.So one contact is for the train and the other for the LED.

Easy.

I don't understand what you mean, can you be more specific?

He means a DPST switch

Two switches wich are mechanically connected and in one package ...

Exit109GTI · 19th August 2005, 09:30 PM

DPST, gotcha!

Would however the parallel transister idea work?

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19th August 2005, 08:08 PM	(permalink)
Exit109GTI	Help With Model Railroad Control Panel Hey everyone, this is my first post on the site. I'm new to electronics, so I hope someone can help me. Building a control panel for a model railroad. The railroad will be split up into a number of blocks, and the control panel will be able to turn on or off power to each block. The power will be a variable 18VDC source. For each block that is powered, I want a LED to light up on the control panel. Here is what I have setup so far. I have a set of mechanic switches, that when on light up a LED, and provides forward bias for a switch transitor. The transistors collector and base is then hooked up to my variable 18VDC source that drives the trains. It's not working, even when the switch is off and the 9V battery is removed, the train is still getting power, and lots of it. My problem I think is that the current breakover limit on my transistor is 600mA, and a N Scale locomotive draws like 1000mA. Would this cause the problem? Would I be able to wire 2+ transistors in parallel to handle more current? Am I even doing this the right way?

19th August 2005, 08:38 PM	(permalink)
Someone Electro	Why not directly switch it whith the mechanical switch. It can probobly 1A __________________ Il give you shocking experience.

19th August 2005, 08:44 PM	(permalink)
Someone Electro	Then have an switch that closes 2 contacts at the same time.So one contact is for the train and the other for the LED. Easy. __________________ Il give you shocking experience.

19th August 2005, 09:11 PM	(permalink)
Someone Electro	Its a single switch but it atcs as 2 switches togeter. You close the switch and its 2 switches will close and you open it an bouth switches will open. This is manly used in mais becose you never know on wich wire is live (the live wire can only shock you!) So it disconects bouth wires to make it a litle safer. Think it as 2 switches sharing the same button. These kind are not as comon as single contact switches but it shod not be to hard to find. __________________ Il give you shocking experience.

19th August 2005, 09:30 PM	(permalink)
Exit109GTI	DPST, gotcha! Would however the parallel transister idea work?