As the worlds energy resources are currently insufficient to meet human needs energy-saving and energy-efficient appliances have to be invented that are readily available and accessible to everyone. To have enough energy to meet human needs and to reduce the waste from the waste of energy resources each year to meet the demand for energy that can be produced by itself. This research presents the construction of a portable DC to AC voltage converter or “Constrution of Portable DC to AC Voltage Converter” which can be operated through a solar cell. By charging energy from the sun and storing energy at the battery. and can also bring electrical energy to use inside the pressure converter There is an inverter circuit that converts voltage from DC to AC so that AC power can be used in daily life. which has a lighting system power socket USB port and helps reduce electricity bills in the house and is convenient to carry From the experimental results of creating a portable DC to AC voltage converter it can be used in daily life and saves electricity and is also clean energy from sunlight that does not cause pollution like a generator that uses oil. be a generator

The objective of this research is to study relation level between personal factor and mixing factor of the marketing and the decision- making to buy the portable computers of Krirk university students. The sample group is 351 Krirk university students. The research tool is the questionnaire. Data analysis is described as percentage value means standard deviation t-test and F-test. The results showed that personal factors including gender age level of education salary and influenced persons are related to the purchase of portable computers of Krirk university students at the 0.01 level. It was also found that mixing factors of marketing price place and marketing promotion has a statistically significant positive relationship with decision-making of the purchase of portable computers of Kirk university students at 0.01.