Low voltage currents are in sometimes AC, and or DC.
In AC PowerEdit
Sometimes, in ac power its listed on transformers or power adapters or power supplies. At 24VAC, it can power a fire alarm control panel, or a HVAC Control board.
For 12VAC TransformerEdit
At a 12vac transformer output can power lanscaping lighting, panels, and any other thing it can do.
DC Voltage Output TransformersEdit
In a DC voltage output transformer, it can put out of voltages like 3VDC, 4.5VDC, 5VDC, 5.8VDC, 6VDC, 8VDC, 9VDC, 10VDC 11.5VDC, 12VDC, and 24VDC.