The Best Current Limiting Resistor Calculator for LED'S - From Quickar Electronics, Inc. Current Limiting Calc - Quickar.com

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Quickar Electronics, Inc.
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The Best Current Limiting Resistor Calculator in the World - From Quickar Electronics, Inc.

Current limiting resistor calculator for Led's

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Single Led - Series Led's - Parallel Led's

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Single led



Supply Voltage
  VOLTS
Voltage Drop Across LED
  VOLTS
Desired LED Current
  MILLIAMPS



Calculated Limiting Resistor
  OHMS
Nearest higher rated 10% resistor
 
Calculated Resistor Wattage
  WATTS
Safe pick is a resistor with
power rating of
  WATTS




Leds in series



Supply Voltage
  VOLTS
Voltage Drop Across LED
  VOLTS
Desired LED Current
  MILLIAMPS
How many leds connected
 



Calculated Limiting Resistor
  OHMS
Nearest higher rated 10% resistor
 
Calculated Resistor Wattage
  WATTS
Safe pick is a resistor with
power rating of
  WATTS



Leds in parallel



Supply Voltage
  VOLTS
Voltage Drop Across LED
  VOLTS
Desired LED Current
  MILLIAMPS
How many leds connected
 



Calculated Limiting Resistor
  OHMS
Nearest higher rated 10% resistor
 
Calculated Resistor Wattage
  WATTS
Safe pick is a resistor with
power rating of
  WATTS

OHMS LAW

The best way to drive LEDS and DC Motors is with Pulse Width Modulation

PWM offers several benefits over a simple current limiting resistor or a current regulator IC

1. Lower Power Consumption

2. Less Heat

3. More Efficient

The current limiting resistor and the linear regulator both have to continiously pass the difference between power in and power out with the result being heat.

In PWM, since the FET is only conducting part of the time, it doesn't use near as much energy, and doesn't get as hot.

All PWM does is chop up the input power ( volts x amps) into "Pulses" of varying width...the wider the pulse, the greater the power is delivered, this gives you control over the brightness of leds, or the speed of small dc motors.

You must always make sure that you either:

A: limit the power going into the pwm circuit so what comes out is not greater than the specifications of your strings of leds, or fans

or

B. limit the power coming out of the pwm circuit , so what comes out is not greater than the specifications of your strings of leds, or fans

 


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