Induction Pointer Watch Battery Tester ----- Battery Tester

Author: Tang Zhenglei The watch battery tester described herein, by using a non-contact method, induction of the drive pulse of the electronic watch second hand, do not open the watch back cover, which is convenient and fast to determine whether the battery and the drive circuit are normal and accompanied by sound. Light displays, with a sound length header, which can measure the voltage of various low-voltage batteries within 3V. The tester can be used as a professional instrument for repair clock. The principle of circuit is as shown on the right, the working principle is as follows: U1C constitutes an oscillating circuit with a frequency of 2 kHz, directly drives the piezoelectric ceramic signaling B. V2 and L, C constitute a high frequency oscillation circuit, enlarged after V1, enters U1B for shaping. The usual high-frequency signal is a constant DC level by the C11 filtering, and the 1T6 and R2 are placed at a high level (h), and when the circuit is in a steady state, the 2 foot is high (h), so 3 The foot is low (L), at which time the U1D single stability circuit in the post-stage is in the clamping state, the VD3 is turned off, and the signal is not working. When the electronic watch is near the tester induced to the L-terminal, the drive pulse signal in the second needle coil makes the oscillation frequency of the V2 to the same low-speed frequency as the pulse signal, and the U1b is planted after V1. Pull the U1A's 1 foot level (L), the 3 foot of the U1A is high (h). Since the level between C2 cannot be mutated, the U1D (11) foot is low (L), and the VD1 is lit. The U1C signal is started, and after about 0.5 s, C2 will be charged by the R1 loop, once charging, U1D (12), (13) The foot begins to turn (L), the (11) foot of the U1D is high (h), and the VD1 is dimmed, and the U1C signal ring is turned off through the diode VD3. The installation commissioning of the circuit is very simple, U1 is four second input CMOS STET trigger CD4093, using DC9V stacked battery, due to circuit steady state, the BL will have a short message. When touching the base of V2 with your finger, the single-organized circuit operation of U1 will be continuously triggered. Indicates the lamp length of the battery capacity. The type of the battery can be selected by ~ a multi-knife slide switch. The entire instrument is: 160mm × 128mmx41mm, gross weight of about 320g. Ordinary pointer electronic meter, generate a drive pulse every second, and there is no ultra-thin electronic watch for second-needle function, generating a drive pulse every 6 to 10 seconds. The strength of the drive pulse signal can be judged from the distance L of the electronic meter. Using the instrument instantly determined that the drive circuit fault is also a failure of the mechanical circuit. In addition to the general electronic watches, the circuit can also sense the working state of the quartz clock, BP machine, mobile phone, electric toy.