24v to 12v Step Down Converter, DROK LM2596 Analog Control Buck Transformer DC-DC Voltage Reducer Regulator Module 36V 24V 12V to 5V 2A Power Inverter Volt Stabilizer with Red LED Display Voltmeter

Parameters:
Input Voltage: DC 4~40V(the input voltage should be higher than output voltage at least 1V)
Output Voltage: DC 1.25~37V(continuously adjustable)
Output Current: 2A(for stable operation), 3A max.
Voltmeter: 0~40V
Voltmeter Accuracy: .+/-0.1V
Internal Oscillation Frequency: 150KHz
There is a large area of copper on its back to enhance heat dissipation

How to adjust accuracy of input/output volt?
(1)Output voltage calibration
Firstly, adjust the right button so that "OUT" LED lighted, the voltmeter shows the value of output voltage; Press the right button for more than 2 seconds,
release, voltmeter and "OUT" LED flashes in synchronization so that you enter the output voltage calibration mode.
Secondly, press the right button (normal speed), the voltage value is adding up a unit; Press the left button, minus a unit; Due to a unit is less than 0.1V,
the minimum voltage display to 0.1V, so you need to continuously press 1-5 times to see the voltmeter change 0.1V, how many times voltmeter change 0.1V by pressing the key, depending on the current display voltage, the higher the voltage, the fewer the number of press.
Thirdly, press the right button for more than 2 seconds, release, to exit the output voltage calibration mode. All parameters set to automatically power down to save.
(2) Input voltage calibration
Firstly, adjust the right button so that "IN" LED lighted, the voltmeter shows the value of input voltage; press the right button for more than 2 seconds,
?release, voltmeter and "IN" LED flashes in synchronization so that you enter the input voltage calibration mode.
Steps 2 and step 3 are consistent with the output voltage calibration method.