(1) Select the rated voltage of the voltage transformer according to the level of the measured voltage, which means that the primary voltage rating of the voltage sensor should be equal to (or greater than) the measured voltage. The ratio is selected according to the ratio of the measured voltage to 100V. (2) The instrument with the voltage transformer should use the 100v AC voltmeter, and the panel scale can be marked according to the magnitude of the measured voltage. (3) The power consumed by the secondary measuring instrument should not exceed the rated capacity of the voltage transformer, otherwise the measurement error will increase. (4) When using the voltage transformer, the primary and secondary must be insured. To prevent accidental short-circuit accidents, the secondary side of the transformer cannot be short-circuited, otherwise the transformer will be burnt. In fact, what people usually call a pinhole camera does not use a pinhole lens. Pinhole lens refers to a lens that uses the principle of small hole imaging to obtain images. It is inexpensive and simple in principle, but its fatal weakness is that too little light passes through the small hole, resulting in too long exposure time. Taking photos with a pinhole lens in sunlight can take anywhere from a few minutes to a dozen minutes, especially when shooting at night with exposure times of up to several hours. Obviously, for a camera that shoots dozens to dozens of frames per second, it cannot meet the requirements. Pinhole lenses cannot be applied to cameras, so there is no "pinhole" camera in the strict sense. As is customary, a miniature camera using a fisheye lens, a flat lens or a conical lens is called a pinhole camera. Pinhole Hidden Camera,4k,High capacity battery Jingjiang Gisen Technology Co.,Ltd , https://www.jsgisentec.com
According to the lens, the lens of the pinhole camera can be divided into three types: fisheye lens, flat lens and conical lens; according to the photosensitive element used, it can be divided into charge coupled element and complementary metal oxide semiconductor; According to the data transmission method, it can be divided into two categories: wireless cameras and wired cameras.