A simple direct injection method for determination of immunity performance of battery operated device

A simple direct injection method for determining the immunity performance of portable battery operated devices is introduced and verified. Two different sized test devices and their immunity results are compared with precompliance immunity measurements made at the frequency range of 2 MHz to 1 GHz. Instead of using a current clamp, the noise is injected via coupling circuitry which consists of resistors and capacitors. The noise is actually injected directly to the equipment under test (EUT) without the accessory cables. The audio breakthrough level was monitored from an additional audio speaker attached to the EUT with cable. During direct radio frequency (RF) injection, the common mode current was monitored from the speaker cable with a current monitoring clamp.