The TJ-56-273 soldering practice board kit contains resistors and capacitors in 0805 packages, SMD aluminum capacitors, SMD exclusions, SMD crystal oscillators, SMD LED lights, SMD diodes, and SMDs in sop14, sop20, TQFP44 and other packages Chip, there are 12 patch group test areas, the welding difficulty is from low to high layout, each group can be tested independently, with short circuit and virtual welding test function, can judge whether the welding is successful according to the display of the LED light, there are 12 groups of patches The test area contains a total of 300 SMD soldering components. Through welding, the welding ability, speed, and circuit maintenance ability of various SMD components can be improved to meet the difficulty of the competition, and it has a self-test function. The welding can be seen when the power is turned on resulting and situations where welding errors occur.

Principle Description:

1. J1 and J2 are the power supply input terminals of the entire SMT board. It can normally work when connected to AC6V. All the LED lights in this kit can normally work when it is working normally. In the beginning, each group of LEDs flashes with water, flashes at intervals, and finally, all lights Turn on all the LEDs to light up, then flash again, and cycle like this to check whether the LEDs are working and whether they are soldered well. If it is found that the corresponding LED does not flicker, it means that there is a welding error or false welding.

2. D1-D4 diodes rectify the AC9V power supply and then pass through each filter capacitor to pin 1 of the voltage regulator chip 78M05 (LED97 is always on, and the rectifier circuit is working normally), and outputs DC5V through pin 3 to supply the entire test circuit.

3. A single-chip microcomputer controls this test circuit to work with 12 groups of 8-bit LED lights. Each group is composed of 1 74HC573 and 74HC164. One group can control 8 LEDs, 12 groups in total. When working normally, all LED lights are on and can flash.

Product parameters:

Product Name: SMD Soldering Test Kit

Product model: TJ-56-273

PCB material: FR-4PCB board

PCB size: 146*100mm

Board color: green board with white characters

Product weight: 62g

Power supply mode: DC DC9V

Applicable objects: junior welding patch personnel

Component Description: Common patch components are used

Number of solder joints: 1079

Number of components: 313

Information: component list, circuit diagram, principle description