Abstract: A voltage tracking circuit is provided. The voltage tracking circuit includes first and second P-type transistors and a control circuit. The drain of the first P-type transistor is coupled to a first voltage terminal. The gate and the drain of the second P-type transistor are respectively coupled to the first voltage terminal and a second voltage terminal. The control circuit is coupled to the first and second voltage terminals and generates a control voltage according to the first voltage and the second voltage. The sources of the first and second P-type transistors are coupled to an output terminal of the voltage tracking circuit, and the output voltage is generated at the output terminal. In response to the second voltage being higher than the first voltage, the control circuit generates the control signal to turn off the first P-type transistor.

Abstract: A method for manufacturing a safety vent on a cover of a lithium-ion battery has punching the cover to form an annular recess and the cover made of aluminum alloy; heating the annular recess to a temperature between 200° C.˜500° C.; cooling the annular recess; and obtaining the safety vent on the cover of the lithium-ion battery.

Abstract: An improved structure of a small lathe and miller assembly includes a lathe, a guide track means, and a miller. The rear side of the lathe bed of the lathe is secured to the guide track means for connection with the miller. The arrangement of a scale on the outer periphery of a rotary chuck, an indexing element at one side of a chuck seat allows setting of the angle of the workpiece held by the rotary chuck, and a curved protecting cover with a scale fastened above the rotary chuck on the chuck seat. A stop plate is secured to a rear side of the chuck seat by a frame plate and a lock handle. A moving block is fixedly connected to a bottom side of a column of the miller. The moving block is provided with dovetail slide grooves for mating with corresponding dovetail tenons of the guide track means. The moving block is screwably secured to guide blocks in the guide track means.

Abstract: A small scale milling machine including a machine base having an upright rotary wheel, a rotary column sleeve fixedly secured to the rotary wheel, a retractable support fixedly secured to the inside of the rotary column sleeve to hold a vertical mounting frame outside the rotary column sleeve, a machine head suspended from the bottom end of the vertical mounting frame and connected to the rotary column sleeve by a dovetail joint and moved vertically along a longitudinal rack on the rotary column sleeve, the rotary column sleeve having a longitudinal track at one lateral side, two stop blocks adjustably fixed to the longitudinal track at different elevations to limit the vertical moving distance of the machine head, and a scale at the front side along the longitudinal track for measuring the vertical moving distance of the machine head.