One of many first classes that makers be taught, when operating that preliminary “blink” code on a microcontroller, is that LEDs must be paired with resistors. In any other case, the LEDs will draw an increasing number of present till they burn out — a course of that’s virtually quick. However a resistor additionally reduces voltage within the circuit, which might make the LED dimmer than you may want. A very good stability is vital, and this straightforward system designed by Leethayer8 will assist you pair your LEDs with the right resistors.
For simplicity’s sake, you could have seen challenge authors say to make use of any resistor, between say 100 ohms and 10k ohms, to restrict the present of an LED—I’ve written such directions, myself. However the resistor’s worth does make a distinction. The next worth lowers the circuit voltage, dimming the LED and drawing much less present. The other can also be true. So, you need a resistor with a price that yields the LED brightness and energy consumption that you really want.
This system helps you establish that resistor worth. By transferring a small jumper between header pins, you possibly can choose the resistor that connects to the LED you place within the socket. As designed, it provides you seven completely different resistors with values from 220 ohms to 10k ohms. It really works with 5V LEDs in the usual through-hole package deal (one cathode leg, one anode leg). By swapping out a number of the elements, you may make this system work with 3.3V LEDs as an alternative or with completely different resistors.
Leethayer8 designed the system to be as simple to assemble as doable. It makes use of a easy two-sided PCB and makes use of solely through-hole elements which are very simple to solder. There may be even a swap to interact a 5V voltage regulator, in case you wish to use a 9V-12V energy provide. Should you’re utilizing a 5V energy provide, that isn’t crucial.
And as a bonus, there’s one closing operate: a take a look at level for a multimeter. That provides you a straightforward strategy to put a multimeter inline with the LED circuit, so you possibly can measure the whole present draw with a particular LED and resistor combo.