This is a design circuit for allows
up to 16 LED clusters illuminate in bar-mode sequence. LED sequencing will
start when the Brake pedal is pressed (or Turn Lights are switched-on) and,
when the last cluster illuminates, all LED clusters will remain steady on until
the Brake pedal is released or Turn Lights are switched-off. This is the figure
of the circuit;
How
this circuti operate?
R5 and D1 are optional: they could be of some utility
in monitoring the sequence frequency set by means of R3.Clusters can be formed
by up to 12 LEDs as shown in the circuit diagram, right side. Common cluster
types usually range from 5 to 10 LEDs. Up to 16 of these cluster driver
circuits, each formed by the LEDs, two transistors and three resistors can be
built and connected to the progressively numbered outputs of IC2 (the first
eight clusters) and IC3 (the remaining clusters). If a number of clusters up to
8 is required, IC3 can be omitted.
Constant output current value for the LEDs can be
changed by varying R10.
The formula is: R = 0.6/I (I expressed in Amperes). Use high brightness, high efficiency red LED types of suitable size and change R10 value to suit LED's Absolute Maximum Ratings. The main circuit, formed by the three ICs and related components is permanently wired to the supply (and D1 will flash) but its 12V positive supply can be wired after the main switch of the car, or an on/off switch can be added.
The formula is: R = 0.6/I (I expressed in Amperes). Use high brightness, high efficiency red LED types of suitable size and change R10 value to suit LED's Absolute Maximum Ratings. The main circuit, formed by the three ICs and related components is permanently wired to the supply (and D1 will flash) but its 12V positive supply can be wired after the main switch of the car, or an on/off switch can be added.
