Lionel crossing flasher #154

May I ask who drew that schematic?

You should be able to substitute the 3055 for the 3904 but may need to adjust the resistor/capacitor values to overcome the lower current gain of the 3055 device.  Depending on how much collector current you need, the devices may need some heatsinking.

Why do you want to go with the higher powered 3055?

Dear Arthur

I got this from another post on this forum. I believe it was GunrunnerJohn that posted it.

Kris

Dear  rrman

If you have a better idea I am listening. Just remember that I am a rookie at this stuff but I am a faster learner. Any suggestion, advise and/or wisdom would be greatly appreciated.

Kris

Hi,

Just stating that the 3055 is also an NPN and you should be able to substitute the 3055 in place of the 3904, but that there may be some adjustment to the resistors to insure enough current to drive the 3055. when the resistors change the capacitors will need changing as the timing will also be changed so lights will flash faster or slower.

Dear rrman

That was a fast reply, thank you. What resistors do you suggest and where would I place the 3055 in the circuit?

Kris

rrman,

I am also a rookie with these things (and don't learn so fast anymore - getting old), but wouldn't the 2n3904's handle enough current for light bulbs? I'm trying to learn here as well.

What Sam was saying was that you would just replace the 2N3904 transistors pin for pin with the 3055 transistors.  You will need two.

Try the 3300 ohm resistors first and adjust if necessary to get the larger transistor to turn on.

The question he was asking was why you would want an alternate flashing circuit with such large transistors.  With a TO-3 case they are larger more difficult to mount (the case is the collector by the way) and unneeded for light bulbs or LEDs.

The 3904 should be good for the current the bulbs draw.  Guessing that the 3055 will work here without component adjustment as collector current is low.

Kris, you can directly substitute the 3055 for 3904.  That is, you remove the 3904s and put the 3055 in their place, being careful which 3055 leads are collector, base, emitter vs the 3904 lead pinouts.  So 3904 collector is now the 3055 collector lead, 3904 base is now to the 3055 base, the 3904 emitter now connects to 3055 emitter.

I assumed that when you were asking about the 3055 you had a higher power device in mind to flash (automotive bulbs or several bulbs, say). 

Dear rrman

I do not know, that is why I am asking this great forum if any would know.  I also have another design but I do not know how to wire it to the Lionel 154. I am trying have a simple design that the light will flash. I have a young son who watches  Thomas the Train and I want to surprise him with this on the Christmas layout. Here is a copy of the other design if anyone can point me in the right direction I would be grateful.

Kris

http://www.mrollins.com/flash3.html

Dear rkenney

Thanks for the reply. Where would I place the 3055 transistors in the 1st diagram to make this work?

Kris

Dear rrman

Thanks for the reply, right now just one Lionel 154 signal. Maybe in the near future the MTH version Lionel 154.

In your 2nd link, the diagram shows the 3055 with the Base, Collector, and Emitter connections identified on the physical package.  Look at rkenney's diagram above and match the B, C, and E to your first schematic.

The two diagrams you supplied are slight variations of the same circuit. It is called a push-pull oscillator. either circuit is fine, but if you already have the 3055s then go ahead and use the 2nd circuit and the values it supplies.

The bulbs of your crossing flasher are 'output 1' and 'output 2' of your second diagram.

 Note that the pink wire is the common lead to the bulbs (terminal 1 on the 154 crossing flasher). This wire also connects to one side of each of the two 39k resistors and the power switch (a push button like a doorbell switch is what I use for the kids to have interaction with the layout). 

Hi

Thanks all. Would this work instead?

http://www.radioshack.com/tip3...020.html#.VJdq0P88KA

Kris

yes, but it will be much easier to use the exact components specified.

Hi rkenney

What 3055 would you suggest and from where.

Kris

HI

Thanks you for all that replied with a fresh  set of eyes I now understand what you folk where trying to tell me. Happy Holidays.

Kris

This is just nit-picking, but the transformer is labelled incorrectly (primary and secondary windings are reversed) and there is no indication of the input voltage that the circuit expects.

If you create the circuit and get it working to your satisfaction in terms of timing, then my suggestion would be to drive a relay with a set of transfer contacts with the capability for multiple loads. That would allow you to use the circuit for any number of applications on your layout that require flashing lamps, fed via bus wires.

Dear Arthur

Thank you for your reply. This is why I got to this forum in the first place to get great advice and input. This project parts are currently in the project enclose waiting for the solder iron to make it way to this project. The solder iron is working on this project currently. https://ogrforum.ogaugerr.com/topic/dc-relay-buzz The only modification that I was going to make that project was adding two buss bars. So I could use one rely to control multiple crossing and gates. I was thinking the same idea in regards using the circuit for other apps. Any ideas or scheme would be greatly appreciated.

Thanks for pointing out that primary and secondary winding are reversed.

Kris