5mm Round Top Blue Slow Flashing 1Hz LED - Ultra Bright

The 5mm flashing round top blue led will begin flashing as soon as you apply power to the led.

In stock

SKU
5MMROUNDTOPFLASHINGLEDBLUE
Color
Blue
Size
5mm Round Top Clear Flashing
$0.22
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Description / 5mm Round Top Blue Slow Flashing 1Hz LED - Ultra Bright

The 5mm Blue Slow Flashing 1Hz LED blinks on and off once per second with a steady, rhythmic pulse — the classic signal blink rate. No 555 timer, no oscillator, no microcontroller required — just apply DC power through a current-limiting resistor and it starts immediately.

Size5mm (T-1 3/4)
Effect~1Hz (60 flashes/min)
Forward Voltage3.0-3.4v
Brightness12,000-14,000mcd
PackageT-1 3/4 through-hole DIP
Drive Current20mA typical

Built for

  • Model railroad grade crossings: Drop two red 1Hz LEDs into a crossbuck housing for prototypical alternating flashers — no Dallee board, no Azatrax controller, just wire and go. 3mm for HO/N scale, 5mm for O/G scale.
  • Security system indicators: The classic slow-blink red LED that says “armed” — mount in a panel bezel on a project enclosure or alarm box.
  • Caution and warning lights: Amber/yellow 1Hz for construction barricade models, runway edge markers, marine navigation buoys.
  • Guitar pedal status blink: Self-blinks at power-up to confirm the pedal is active — no firmware, no PWM code.
  • Beginner electronics project: The simplest possible blinking circuit — power + resistor + LED. No code, no IC, no breadboard. Instant reward for a first-time builder.

Makeshift controller trick: Wire this LED in series with standard LEDs, and the entire string will blink together at 1Hz. One flashing LED as the “master” drives several regular LEDs in a synchronized blink.

Why this instead of a 555 timer? A 555-based blinker needs the timer IC, two resistors, a capacitor, and a breadboard. This LED replaces all of that with a single component. Trade-off: you cannot adjust the blink rate. If 1Hz is what you need, this is the simplest solution.

Polarity matters — long lead is positive (anode). Add a current-limiting resistor matched to your supply voltage. Drop-in replacement for any standard 5mm LED — same footprint, no circuit changes.

Resistor quick reference (20mA):
SupplyResistorRating
5V100Ω1/4W
9V300Ω1/4W
12V470Ω1/4W
15V*620Ω1/2W
18V750Ω1/2W

*Use 15V instead of 12V for vehicle/alternator sources to account for charging voltage (13.8–14.4V).

Full LED Resistor Calculator → for other voltages, series strings, and parallel configurations. Or skip the math with our 20mA Current Limiter (2–45V DC).

Frequently Asked Questions

No. Self-flashing LEDs have a fixed blink rate set by the internal IC (1Hz, 2Hz, or 6Hz depending on the variant). If you need adjustable timing, use a standard LED with a 555 timer circuit or an Arduino.
Wire a self-flashing LED in series with one or more standard LEDs, and the entire string will blink together. The flashing LED acts as a current gate, controlling the pattern for all LEDs in the chain. This lets you animate multiple LEDs with a single flashing LED — no separate controller needed.
No. Animated LEDs with built-in ICs require DC power. On AC, the IC cannot function and the LED will not produce the intended effect. For AC sources, convert to DC first with a bridge rectifier.

DC power required: Animated LEDs (flashing, flickering, fading) require DC — they will not operate correctly on AC power. If you're working from a low-voltage AC source such as a model railroad transformer or DCC output, you must convert to DC first using a bridge rectifier.

Power SourceBridge Rectifier100µF Capacitor
DC power supplyNoNo
12V AC landscape transformer
Required
Required
DCC track power
Required
Required

Full wiring guide with circuit diagrams →

Complete your build

Sold individually (1 LED per quantity ordered).

PCB Design: KiCad footprint: LED_THT:LED_D5.0mm (built-in with KiCad). EasyEDA: search “LED_D5.0mm” in the built-in library. Download KiCad files ↓

Specifications are sourced from manufacturer data and may be updated without notice. While we work to keep product information accurate, always verify critical parameters against the manufacturer's datasheet for production designs. Found an error or discrepancy? Let us know — we genuinely appreciate the correction.

More Information

Size 5mm Round Top Clear Flashing
Color Blue
Animation Type 1Hz Flashing / Blinking On / Off
Luminosity/Brightness 12,000-14,000 mcd
Forward Voltage 3.0-3.4v
Current 20mA
Wavelength 460-465nm
Viewing Angle 20-30 Degrees
Mount Style Through Hole (DIP)
Lens Color Clear
LED Brightness Class Super/Ultra/Extreme

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