Testing LM2596 Variable Voltage Regulator

Our LM2596 Variable Voltage Regulator (discussed previously here: regulator with display) has finally arrived after its long journey from China.

LM2596 variable voltage regulator with display

The first image above shows the input voltage as being 13.8V (which was accurate to <0.1V). The second image below shows the output voltage which we set by adjusting the small brass screw in the blue potentiometer to be 5.0V (which was also accurate to <0.1V).

lm2596 with LCD voltage display

The build quality and quality of the components used is excellent throughout, the LCD is bright, and the addition of a red LED and a green LED to indicate whether the input or output voltage is being displayed is very useful. Selecting whether to display input or output voltage is achieved using a small button on the regulator board. In addition to screw-in terminals for connection of the input and output wires, there are also holes with solder pads in both fine and medium sizes so that different sizes of wire can be more securely attached if required.

The only bad point would be that there is no option to turn off the LCD when it is not needed – i.e. it needs three options (display input voltage, display output voltage, or display nothing) instead of the two it has. The LCD draws approximately 25mA all the time, so will take 0.6Ah of charge out of a battery every 24hrs which is a lot. Another 10mA seems to be the quiescent current lost in the regulator when nothing is connected to the output but it is still regulating voltage.

We can think of many uses for these voltage regulators which are made easier thanks to the on board display – first and foremost for small battery charging from a 12V battery, and/or powering USB charged devices (using a 5.0V output). For battery charging of say four series connected NiMH rechargeables, you would just set the output voltage to say 5.8 or 5.9V and connect it to the battery pack with the correct polarity.

Apart from having slightly high self-power consumption, these regulators are excellent quality and fantastic value.

If you are interested in purchasing one of these regulators, click here: LM2596 Voltage Regulators. Prices are around £3.50 each or £17 for five including air mail delivery from China.

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