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In this video we use our Peak Electronic Design Atlas DCA75 Pro Semiconductor Analyzer to measure the forward voltage of ten different LEDs which I keep in stock.
In the following table the values are computed for VS = 5V and I = 20mA.
| Size | Colour | VF | VR | RS |
|---|---|---|---|---|
| 10mm | RED | 1.890 | 3.110 | 156 |
| 10mm | GREEN | 2.030 | 2.970 | 149 |
| 10mm | BLUE | 2.643 | 2.357 | 118 |
| 10mm | YELLOW | 1.939 | 3.061 | 153 |
| 10mm | WHITE | 2.615 | 2.385 | 119 |
| 5mm | RED | 1.889 | 3.111 | 156 |
| 5mm | GREEN | 1.995 | 3.005 | 150 |
| 5mm | BLUE | 2.710 | 2.290 | 115 |
| 5mm | YELLOW | 2.019 | 2.981 | 149 |
| 5mm | WHITE | 2.775 | 2.225 | 111 |
- VS
- Supply voltage, e.g. 5 V.
- I
- Desired LED current in milliamps, e.g. 20 mA.
- VF
- Forward voltage, as measured; e.g. 1.8 V.
- VR
- Voltage across resistor = VS – VF.
- RS
- Series resistance to use, in Ohms = VR / I.
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Following is a product I use picked at random from my collection which may appear in my videos. Clicking through on this to find and click on the green affiliate links before purchasing from eBay or AliExpress is a great way to support the channel at no cost to you. Thanks!
Yum Cha 13-in-1 Multi-function Digital Display USB Voltage Current Power Meter |
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