Hi,
still a question...
* Usually a transformer has AC output, (but there are electronic transformers with DC output. Especially for LEDs there are different LED drivers. Some are current controlled, and/or somehave PWM brightness control)
Maybe you can attach a datasheet or a picture of your transformer..
* but LEDs and LED stripes usually work with DC (But also here there are different types.. Some for voltage control, some for current control, Some are made to work on a 12V AC system...)
Please give technical data on your used LEDs.
Klaus