Its small size was made possible by pulsing current to the Texas Instruments TMS1802 "calculator on a chip" integrated circuit, reducing the power consumption more than tenfold.

The Executive was highly successful, making £1.8 million of profit for Sinclair and winning a Design Council Award for Electronics.

[8] It was well received by both domestic and foreign markets, and US$1.5 million worth of Executives were sold in Japan in early 1974 at six times the price of Japanese models.

[10] The Executive impressed the engineers at Texas Instruments, who had used the same chip to produce a longer and wider calculator that was over three times as thick and a great deal more expensive.

[11] A Sinclair Executive purchased by a Russian diplomat exploded in his breast pocket, allegedly leading to an official Soviet investigation.

[1] The case, designed by Iain Sinclair,[14] was made of black injection-moulded polycarbonate and required flexible glue to hold the two halves together.

[7] It was discovered that an early prototype continued to work if the batteries were disconnected and then reapplied quickly enough, as the capacitors in the circuit could hold a charge for up to five seconds.