In designing any LED circuit it is the current that you need to control. The manufacturer generally specifies the maximum mA or the typical operating current. You probably want to keep to about 75% of the maximum for long life. A cut and try approach is best, because different colors and types of LEDs have different forward voltage drops. When using a 12v supply you can put 2 or 3 LEDs in series (+ to -, + to -, etc.). If you start with 1000 ohms the current will be at a safe low level. Put a meter in series with the circuit to measure current and then gradually decrease the value of the resistor to get the current up to a reasonable value. I like 15 to 20 mA for LEDs of the usual size. If 2 or 3 in series isn't bright enough, do another parallel branch with its own resistor. Larry A. home-brew LED maplite in AC outlet and LED behind heater controls next, the domelites
nick greenaway wrote: >does anyone know what parts i need to get at radio shack to drop >12.6v down to 3.7v (i cant remember the amps) for an LED driver? >im sure someone out there has done it >thanx >nick > >__________________________________________________ >Do You Yahoo!? >Tired of spam? Yahoo! Mail has the best spam protection around >http://mail.yahoo.com > > > |
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