Fast blinking LED bike light circuit

This is a fast blinking LED bike light circuit For safety when the bike at night. We use two-NPN-PNP transistor oscillator circuit and RC circuit only show on 4 LEDs use low current.

We take the four LEDs to parallel because each LED use voltage about 3 – 4.5V
We want this circuit for long time using so use the LED voltage is 3V only. And makes them to blinking as the LED flasher.

Testing the LEDs in parallel
Figure 1 Testing the LEDs in parallel. They use current about 0.077A.
But we use them in switching so low

Fast-blinking-LED-bike-light-circuit
Figure 2 the circuit diagram of Fast blinking LED bike light

How this circuit works
This is simple transistor oscillator circuit as flip-flop. We use a simple RC. Here is the schematic of my two-transistor LED flasher: The RC circuit is connected to the base of the NPN transistor (2N3904) and it gives the signal to the PNP transistor (2N3906) to turn on the LED. When the PNP transistor is ON, it discharges the capacitor and it turn off itself, so the cycle repeats again.

How to builds
Today I want tech my son assemble circuit on cardboard because he did not want to use PCB. We use the cardboard from old Desktop calendar that unused. We design the components layout on a paper. Then stick it on the cardboard with glue. As Figure 3

the layout on cardboard
Figure 3 the layout on cardboard

to use iron spikes holes to insert pins
Next step, to use iron spikes holes to insert pins as Figure 4

put the components on layout
And Then, put the components on layout as Figure 5

to use pin devices Or copper wire connected
After that, to use pin devices Or copper wire connected as Figure 6

Solder pins and copper wires to complete
Next, Solder pins and copper wires to complete. as Figure 7

Then, Test to use it as video below

And then,Apply glue pin devices, the access point and devices. In order to prevent vibration. As Figure 8
Apply glue pin devices

Last, To bring the circuit trial, mounted on a bicycle as Figure 9
Fast-blinking-LED-bike-light

and test it at night as video LED flasher good look and low current use.

           Eleccircuit highly recommends EasyEDA for PCB design and order

Low Cost & Fast PCB Prototypes - EasyEDA

Only $8.21 for 10 pcs, 2-Layer 100x100mm PCBs, 2-3 days delivery

 

9 Comments

  1. Salim Khan March 6, 2016
  2. momename March 10, 2016
  3. phillip April 6, 2016
  4. Michael wolf April 15, 2016
  5. David June 19, 2016
  6. Adrian June 24, 2016
  7. chayapol garaipoom June 26, 2016
  8. chayapol garaipoom June 26, 2016
  9. Iqoos August 29, 2016

Add a Comment

Your email address will not be published. Required fields are marked *