The DM2, launched in February 1975, was far more successful than its predecessor the DM1 (as well as being a technically superior product). It had been designed by Sinclair's John Nicholls, who used a mixture of chips and components which were already in service in other Sinclair products. Only one new chip, from General Instruments Microcircuits, was utilised. This allowed Sinclair to take advantage of bulk buying to lower the overall cost of the device.

The meter itself was well-designed, doing its work to a reasonably good standard (1% accuracy) and being easy to assemble and test. It immediately found favour in the scientific, hobby, retailing and educational fields, selling very well and making the company a lot of money. For once, production problems had been tackled from the outset and high initial demand could be satisfied. Some 30,000 units were sold, 80% of them overseas.