<p><em>In this study, a supply voltage at peak breaker is made to do the plug discharge test. Plug discharge (capacitor residual voltage)  testing on IEC 60335-1 is a challenge for engineers. Requirement for the test are disconnecting supply voltage from the Equipment Under Testing (EUT) at its peak value. Most laboratory did this test manually, so the test might be carried out repeatedly so that the requirement is obtained. This system is using zero crossing detector and timer for detect the peak waave. The zero crossing detector circuit find the time when the voltage cross the 0 volt as the initial reference for termination. Microcontroller with Timer feature is used to delay the disconnection time from the 0 volt point or a quarter period of the power line. Relays are used as voltage breakers. From the experiments, it is necessary to add a compensation time due to the relay response time so that the system could do the supply voltage break at it’s peak wave. This system works properly with error 1.6% and with this means plug discharge testing could be finished in only one trial.</em></p>

Power generation from photovoltaic (PV) power is affected by radiation intensity of the sun and temperature of the environment. PV can produce maximum power, when its position to the sun is optimum. The objective of this research is to control PV position toward the sun by using an active tracking system in order to produce optimum electric power. Two Light Dependent Resistor (LDR) sensors were placed in the east and west side of the PV, and a balancer was placed in between. When the sun is on the east side from 7 a.m to 11 a.m the east LDR was exposed to light, while the west LDR was covered by balancer. When the sun is on the west side from 1 p.m to 5 p.m, west LDR was exposed to the light, while the east LDR was covered by balancer. The light intesity difference that is received by each LDR showed that an active tracking system would conduct a control action to PV position so that it will be perpendicular to the sun. The testing result showed that the difference of maximum power was 39,88 watt. It also showed that the active tracking system with single axis type could become a reference for maximum solar utilization.