Mysterious circuit
From Tardis Wiki, the free Doctor Who reference
The mysterious circuit was a device that Sarah Jane Smith had inside her attic at 13 Bannerman Road. (TV: Invasion of the Bane)
Behind the scenes
According to the official SJA website the mysterious circuit came from Shenyang in China. It was found there in the 1880s. The function and the origin was unknown, but the advanced design suggested that it was possibly used by time travellers.[1]
The prop in this episode was originally used in The Girl in the Fireplace episode of Doctor Who to open the 'skylight' on the SS Madame de Pompadour
