Quote:
Originally Posted by RAJAH235
ps. If you find it necessary to dim them, just wire a 20 Kohm to 50 Kohm pot in the positive lead, (eg; in series), with the LEDs.
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Quote:
Originally Posted by 74tuc
20K to 50K in series with each LED?
The LED brightness may range from very dim to off.
This scheme does not lend itself for future expansion as previously mentioned and would be most user unfriendly for adjusting brightness in the field.
To design a brightness control and allow for future expansion will take a re-design along the following lines:
Maintain the original circuit arrangement with the current sharing resistors about 20 ohms (guess - not calculated) then control the whole load with a pulse width modulated (PWM)source (555 timer and small power mosfet). The PWM scheme is suggested for efficiency and because of low operating voltage(6V).
Jerry.
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Possibly showing my ignorance of electrical circuits here, but I assumed that Laurie was suggesting a single potentiometer in the circuit, placed in the wiring segment just after the +ve terminal but before the 1st LED?
Cheers
Dennis