TechCrate 001 — Railroad Crossing Signal

Build a railroad crossing signal with two red LEDs that flash in turn. Use a 555 timer, resistors and a capacitor to explore how electronic timing controls the lights.

• 555 timer chip
• Red LEDs
• 47K resistor
• 470 ohm resistors
• 10µF capacitor

Breadboard, 9V battery, Battery snap connector, Jumper wires.

Subscriber instructions PDF · Build video and customer files

Optional: compare the timing resistor values with power disconnected, then watch how the flashing changes. The complete build and its checks work without a meter.

ProTechTrader Large Screen Digital Multimeter PDM-711