Parameter:
Product name: Advanced full-chip welding practice board
Board size: 75*45MM; Board thickness: 1.6MM;
Number of components: 149; Power supply voltage: DC4.5~12V;
Board material: international standard board, blue group solder layer, all solder pads are tin-plated, high-strength anti-fire and anti-drop material, which can be repeatedly disassembled and assembled.
Features:
The new glass fiber spray tin chip component welding practice board kit is based on the summary and improvement of years of professional teaching and competition practice. The circuit board design is novel and scientific. The PCB board is made of high-quality glass fiber board, and the large factory’s full-process tin-spraying treatment is excellent in quality. The training is specially optimized for the design, which is convenient to withstand multiple desoldering and can improve the efficiency of use. It is especially suitable for training in electronic assembly skills competitions, continuously improving the welding process and speed, and can also be used as electronic assembly competitions and exams.
Circuit principle:
After the SMD components are soldered, they are energized to form a running water lamp to test the soldering effect. Since the voltage across capacitors C1-C9 cannot change suddenly when the power is turned on, pin 2 of U1 NE555 is at a low level, and pin 3 of the output terminal is at a high level. When the power supply is charged to C1-C9 through R1-R10 and RP1-RP5 by 2/ 3 Power supply voltage, the level of pin 3 of the output terminal changes from high to low, 555 is internally turned on, and capacitors C1-C9 are discharged through pin 7 of 555 until the voltage across C1-C9 is lower than 1/3 of the power supply voltage. The level of pin 3 changes from low to high again, and C1-C9 are charged again, thus forming a cyclic oscillation. Changing the size of RP1-RP5 can change the output frequency of the oscillator. The 555 clock oscillation signal is continuously added to the 14 feet of U2 CD4017, and 10 transistors are connected to the 10 output terminals of the 4017 to drive 10 LEDs, and the 10 outputs of the 4017 Under the action of the clock signal, the terminals generate high level in turn, then L1-L10 are lit once, forming a flow LED effect.
Welding and testing instructions:
1. Precautions for welding
a. There are no welding direction requirements for resistors, capacitors, and exclusion devices.
b. The black end of the diode 1N4148 is the negative electrode, pay attention to the welding direction.
c. The end of the LED with green color is the negative electrode, and the silk screen of the corresponding board faces the downward direction.
d. The triode is welded in the direction of the silk screen pattern on the board.
e. Place the small dots on the chip notch or corners corresponding to the small silk-screen dots on the board for welding.
2. Test instructions
a. A or U3 chip test point (B is a U4 chip test point), a multimeter detects whether the two solder joints are connected or not, and it can detect whether the adjacent pins of the chip welding are short-circuited.
b. C is the R0402 resistor 1K series circuit, the resistance value of the two solder joints measured by the multimeter resistance file is approximately equal to 10K.
c. D is the R1206 resistor 1K series circuit, the resistance value of the two solder joints measured by the multimeter resistance file is approximately equal to 10K.
d. Circuit function test: After power-on, the L1~L10 running water lamps light up normally.
Package Included:
| Component list |
| Component name |
Component location |
Encapsulation |
Quantity |
| Chip resistor 10K |
R1~R10 |
R0603 |
10 |
| Chip resistor 100r |
R11~R60 |
R0805 |
50 |
| Chip resistor 1K |
R61~R70 |
R0805 |
10 |
| Chip resistor 1K |
R71~R80 |
R0402 |
10 |
| Chip resistor 1K |
R81~R100 |
R1206 |
20 |
| Chip capacitor 105 |
C1~C10 |
C0805 |
10 |
| Chip drain 100r |
RP1~RP5 |
8P4R-0603 |
5 |
| Patch LED red |
L1~L10 |
LED0805 |
10 |
| Chip diode 1N4148 |
D1~D10 |
LL-34 |
10 |
| SMT s8050 / j3y |
Q1~Q10 |
SOT-23 |
10 |
| Chip NE555 |
U1 |
SOP-8 |
1 |
| Chip CD4017 |
U2 |
SOP-16 |
1 |
| Chip tm1621 |
U3,U4 |
LQFP-44 |
2 |
| PCB board |
|
|
1 |
Availability: 
Shipping: Free Airmail 
Reviews
There are no reviews yet.