1.   It also has to be plugged into house current.

2.   Lionel also introduced its first transformer, which could reduce house current to a lower voltage suitable for toy trains.

3.   The radios can run either on batteries or on house current with a battery back-up.

4.   They require a transformer to convert house current to a lower voltage similar to systems for outdoor lighting.

5.   This device attaches to the main house current and converts it to the lower voltage.

6.   Units that run on house current use metal oxide semiconductor technology.