Partial discharge (PD) detection technique can be used to inspect power equipment interior insulation status to prevent breakdown. The main purpose of this paper is to develop a simple PD detector that is based on the MSP430 microcontroller and combined with a bandpass filter / amplifier that was previously designed in the NDE laboratory. The simple detection system can be used for long-term monitoring, generating precision real-time clocks, and counts the number of PD events from acoustic emission (AE) waveforms. We applied the simple PD detector to sense the discharge signals in power cable and cast-resin dry type current transformers. The counting numbers of PD signals show that the new designed detector can provide an early alarm to the condition of PD in the power equipments. In addition, by applying multiple detectors, we can locate the PD source based on the counted number of PD events. The system is low cost as compared with the commercial PD apparatuses.