Electromagnetic Interference from Pocket Calculators

Presented are the results of an investigation of the near-field Electromagnetic Interference (EMI) associated with the operation of pocket calculators. A review of the regulations governing the permissible levels of interference from portable electronic equipment is undertaken, and subsequently, the results of EMI measurements on three pocket calculators are presented. The results indicate that near-field EMI levels are of sufficient magnitude to make questionable the unrestricted operation of a pocket calculator in an electromagnetically sensitive environment, such as found on an aircraft flight deck. Finally, a simple and inexpensive means of eliminating this interference is investigated.