EK003 LED Tester
Part.no: 41017561
This circuit is a simple constant current LED tester and can be useful in any situation where color or brightness of an LED needs to be evaluated.
The circuit is built around an LM317 voltage regulator configured constant current source, which is well suited for driving LEDs.
The DIP switch on the board is used to set the drive current and can be adjusted from 5mA to 25mA in steps of 5mA.
To test an LED, turn on the power switch, set the desired drive current, and touch the LED leads to the large terminals.
If the LED is connected with incorrect polarity, it will not light, but no damage will occur. Simply reverse it and it will operate correctly.
There is no detailed assembly guide for this kit. Follow the component markings on the PCB and verify the values against the component list.
Component list
| Name | Qty. | Part.no. | Marking |
|---|---|---|---|
| Voltage regulator LM317 | 1 | 40350317 | LM317T |
| DIP switch 4-pol | 1 | 40220007 | |
| Resistor 249ohm | 5 | 40702249 | |
| LEDs | 2 | LED 5mm | Mixed colors |
| Slide switch | 1 | 41011898 | |
| Battery holder 9V | 1 | 41000885 | |
| Screw M2.5 8mm | 3 | 41013913 | |
| Hex nut M2.5 | 3 | 41013902 |
Assembly guide
The assembly of this kit is very simple. There are only four different components to be soldered onto the PCB, and the risk of making mistakes is low.
It is important to install the LM317 voltage regulator and the red DIP switch with the correct orientation. Refer to the markings on the PCB.
The five resistors should be soldered in their respective positions. They all have the same value, and orientation does not matter.
The wires from the battery holder must be inserted into the correct holes on the PCB. The red wire goes to the hole marked with a plus symbol, and the black wire goes to the elongated hole.
Användning
Simply touch the leads of the LED you want to test to the pads or holes on the PCB marked "LED-" and "LED+".
The current can be adjusted in steps from 5mA up to 25mA:
| 1 | 2 | 3 | 4 | Current |
|---|---|---|---|---|
| 0 | 0 | 0 | 0 | 5mA |
| 1 | 0 | 0 | 0 | 10mA |
| 1 | 1 | 0 | 0 | 15mA |
| 1 | 1 | 1 | 0 | 20mA |
| 1 | 1 | 1 | 1 | 25mA |
Simulation ↗
Schematic
