I am a student trying to learn about PLCs. I was buying a light (beacon) to install on my PLC and had a question about the output voltage. On the PLC I saw that the outputs are 24 V DC. On the beacon I am ordering, the options are: 12V AC/DC Full Voltage 24V AC/DC Full Voltage 120V AC Full Voltage 240V AC Full Voltage I am assuming I should order the 24 V AC/DC, but I was wondering what does AC/DC mean. Is AC/DC different then just DC. Is that even the correct one since the output card provides 24 V DC? Thanks!