For surface-mount designs, Rideon’s PFS series of power surface-mount device (SMD) film resistors can handle up to 35 W. Phil Ebbert , vice president of engineering, is in charge of resistor
I do the same with resistors and inductors. For semiconductor devices, I have all the small-signal diodes in one drawer, all the zeners in another, all the rectifiers in another (again, with TH in their own drawer becuase they're big) I have a drawer each for red, green, yellow and blue LEDs, and my NPN and PNP transitors get separate Driving a large number of LEDs with a constant current can be done with either a lengthy series connection or by driving multiple strings in parallel. But connecting many LEDs in a long series string poses high-voltage and single-point failure issues. Similarly, powering multiple strings in parallel requires multiple current regulators, one forAssume the LED will have a forward drop of around 1V (could be less, could be more). Start with 1mA of forward current and go from there. ILED = 12V − 1V 1mA = 11kΩ I L E D = 12 V − 1 V 1 m A = 11 k Ω. Then, install the resistor in series with the LED, apply power, and measure the battery voltage and the resistor voltage to actually
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