Linear Voltage Regulator Board 5V/3.3V/1.8V

These boards integrate the STM LD1117S low drop out voltage regulators with their required stability capacitors. They are best used for powering low power circuits like microcontrollers and sensors. You can regulate a max voltage of 15V down to 5V, 3.3V, or 1.8V depending on the model, and each regulator can output a max current of 800mA. They also have integrated overcurrent protection and thermal shutdown. To use, simply connect your common ground to GND, connect your low voltage circuit to OUT, and connect up to 15V to Vin.

The drop-out voltage of these regulators is ~1.2V which means you need to supply at least 1.2V more than the output voltage for the regulator to work properly. As an example, for the 5V version you’d need at least 6.2V, for the 3.3V version at least 4.5V, and for the 1.8V version at least 3V.

Because linear regulators burn off excess voltage, which generates heat, it is most efficient to use an input voltage closer to the output voltage. You can burn off up to ~0.9W without a heatsink. For example with the 5V output model, using 12V and pulling 500mA would burn 3.5W and definitely require a heatsink. But using 7V and pulling 400mA only burns 0.8W and would not require a heatsink. You can calculate the wattage using this equation: (InputVoltage – OutputVoltage) * OutputCurrentInAmps.

The capacitors on the PCB are especially important for the voltage regulator because they can protect it from voltage spikes when your power supply turns on. Without them, the voltage regulator can be easily damaged and allow the high input voltage to pass throughout the rest of your circuit.