Top Tip; the pump and lights you have must not draw more than 7.2 watts in total power.
12 Volt Power Supplies (Transformers) with 2.1mm adapter for Dolls House Lights
Dolls House Transformer and or Connection Cable 12 Volt Miniatures Lighting 50
12v AC 60W Waterproof Garden Transformer power supply outdoor 12 volt 60 WATT
Manrose T12 12 Volt SELV Transformers for Low Voltage Fans (T12T T12S T12P T12H)
12 volt 30VA 2500mA Watt Transformer Outdoor Water Feature Lighting IP44 - D4C
CHASSIS TRANSFORMER 12 VOLT 100VA for LIGHTING or MODEL RAILWAY PROJECTS
