The purposes of the research were; 1) to study the relative rotation of AC-generator 2) to study the angular velocities of magnetic coil and permanent magnetic influence generating voltage of AC-generator and 3) to construct predictive equations of generating voltage of AC-generator. By the 12-V 6-pole alternator of motorcycle Pearson’s correlation and regression analysis the findings revealed that: 1) At the lowest relative angular velocity of 376 rpm the generating voltage is 3.28 V. While the highest relative angular velocity of 2280 rpm the generating voltage is 22.98 V. 2) The angular velocity of permanent magnetic has great influences on generating voltage than the angular velocities of magnetic coil at the .01 level of significant and 3) function as below : Generating voltage = 0.806 (Velocity of permanent magnetic) + 0.634 (Velocity of magnetic coil)

The purposes of the research were; 1) to develop the detection of the transparency of air dried rubber sheet (ADS) using solar cell module 2) to find the average voltage according to the standard ADS grade market level and 3) to construct predictive equation of output voltage of the transparency machine. Samples of this study obtained by a purposive sampling technique was the standard ADS of 652 sheets. The instruments consisted of a multi-meter and transparency machine. For statistical analysis t-test (independent samples) and f-test (one-way ANOVA) were employed. The findings revealed that: 1) The ADS transparency machine consists of solar cell module at the error of 6% 2) The average voltage according to the standard ADS classify market level of 1 2 3 and 4 are 3.41 2.80 2.49 and 1.91 V. respectively 3) The market level and thickness of ADS altogether were the variables that could predict the output voltage of the transparency machine at 86.5 %