[tr1]

Does anyone have a printable schematic for the alternately
flashing ckt. for railroad crossings
Thank you,
Regards, tr1

 

[Tom_C]

Scroll down on this page and you'll find a flashing circuit:

https://www.electronics-tutorials.ws/waveforms/555_timer.html

 

[wvgca]

this kit doesn't use the 555, just a couple of transistors instead, but it's very close to actual flash rate, and the kit is less than a buck for all parts, including the pcb and shipping ..

 

[rkenney]

The circuit you want shown above is a simple two transistor push-pull oscillator.



RC value controls the rate. 555 is overkill, you can wire the above circuit with a small piece of perfboard and power with a 9 volt battery or a wall wart.

 

[rrswede]

wvgca, what is the source?

Thanks, swede

"this kit doesn't use the 555, just a couple of transistors instead, but it's very close to actual flash rate, and the kit is less than a buck for all parts, including the pcb and shipping"

 

[wvgca]

wvgca, what is the source?

Thanks, swede

the listing has ended, but here is the same one on ebay ..
https://www.ebay.ca/itm/5pcs-DIY-Kit-5MM-LED-Simple-Flash-Light-Simple-flash-Circuit-Production-Suite-/352930647793?oid=361767169383




the LEDs included are 5mm, so the size is pretty small, lol

 

[rkenney]

If you want to flash bulbs as in the 154 this circuit will work:

 

[wvgca]

note that the above circuits do not include occupancy detectors / sensors, if that is what you had in mind ..

 

[rrswede]

Thank you for the responses, wvgca and Bob.

Wvgca, I did not have occupancy detection in mind. I was interested because of your reference to cost. Very inexpensive.

The crossings on my layout already have flashing units built using the same diagram as you posted, Bob. They have served me well.

swede