Photos: Early analogue torpedo simulator

This is the PACE TR-48, an analogue computer on display at the National Museum of Computing at Bletchley Park.

The machine was made by Electronic Associates to simulate the firing of torpedoes underwater.

Peter Chilvers, volunteer at the National Museum of Computing, said: "In the early days of computing, digital computers weren't fast enough to do certain sorts of calculations, so analogue computers would work by having electronic circuits. The voltage or current within an analogue computer can be continuously varied."

Photo credit: Andy McCue/silicon.com