Ranking of Chinese circuit board processing enterprises

Electronic master circuit diagram collection

First, regulated power supply

1, 3 ~ 25V voltage adjustable voltage regulator circuit diagram

The voltage regulator can be adjusted in the range of 3.5V ~ 25V, the output current is large, and the adjustable voltage regulator tube circuit, so as to obtain satisfactory and stable output voltage.

Working principle: After the rectifier filter DC voltage provided by R1 to adjust the tube base *, so that the adjustment tube on, V1 on voltage through RP, R2 to V2 on, and then V3 also on, then V1, V2, V3 emission and collector voltage no longer change (its role is the same as the regulator). Adjust RP, can get a stable output voltage, R1, RP, R2 and R3 ratio determines the voltage value of the circuit output.

Component selection: Transformer T uses 80W ~ 100W, input AC220V, output double winding AC28V. 1A for FU1 and 3A ~ ** for FU2. Use 6A02 for VD1 and VD2. RP uses about 1W ordinary potentiometer, resistance value is 250K ~ 330K, C1 uses 3300µF / 35V electrolytic capacitor, C2, C3 uses 0.1µF stone capacitor, C4 uses 470µF / 35V electrolytic capacitor. R1 uses 180 ~ 220Ω/0.1W ~ 1W, R2, R4, R5 uses 10KΩ, 1/8W. 2N3055 was selected for V1, 3DG180 or 2SC3953 for V2, and 3CG12 or 3CG80 for V3

2, 10A3 ~ 15V regulated power supply circuit diagram

Whether the maintenance of the computer or electronic production can not be separated from the regulated power supply, the following introduces a DC voltage from 3V to 15V continuous adjustable voltage power supply, large current up to 10A, the circuit with temperature compensation characteristics, the most advanced standard voltage source integrated circuit TL431, so that the stability accuracy is the highest, if there is no requirement, basically can meet the normal maintenance use, The circuit is shown below.

Its working principle is divided into two parts, part is a fixed 5V1. * The second part is another route 3 to 15V continuous adjustable high current voltage regulator circuit. The circuit is very simple, by the transformer secondary 8V AC voltage through the silicon bridge QL1 rectified DC voltage after C1 electrolytic capacitor filtering, and then by the 5V three-terminal regulator LM7805 does not use any adjustment can be produced at the output end of the fixed 5V1A regulated power supply, the power supply can be used as an internal power supply when the maintenance of the computer board. * Two parts and ordinary series type voltage regulator power supply is basically the same, the difference is the use of temperature compensation characteristics, the best standard voltage source integrated circuit TL431, so the circuit simplification, cost reduction, and voltage regulator performance is very high. In the figure, the resistor R4, the regulator TL431, and the potentiometer R3 form a continuously adjustable constant voltage source, providing reference voltage for BG2 base *. The regulator TL431 has a continuously adjustable voltage value, which determines the large output voltage of the regulator power supply. If you want to expand the adjustable voltage range, you can change the resistance values of R4 and R3. Of course, the secondary voltage of the transformer should also be increased. Transformer power can be flexibly mastered according to the output current, secondary voltage about 15V. The rectifier tube QL for bridge rectifier uses a 15-20A silicon bridge, which is compact and has a fixing screw in the middle, which can be directly fixed on the aluminum plate of the housing for favorable heat dissipation. 

Adjust the pipe is a large current NPN metal shell silicon tube, because of its heat is very large, if the case allows, try to buy a large heat sink, expand the heat dissipation area, if you do not need a large current, you can also change the power of a small silicon tube, so that the volume can be smaller. The filter uses 50V4700uF electrolytic capacitor C5 and C7 in parallel, respectively, to make the large current output * stable. In addition, this capacitor should be purchased with a relatively large volume, and those with a small volume should also be marked 50V4700uF as far as possible. When the voltage fluctuations are frequent, or when not used for a long time, it is easy to fail. Then talk about the power transformer, if there is no ability to wind their own, can not buy ready-made, you can buy a ready-made more than 200W switching power supply instead of transformer, so the voltage performance can be further improved, the production cost is not too much, other electronic components without requirements, after installation without too much adjustment can work normally.

Number of layers

One to six layers

The number of layers refers to the number of electrical layers (copper layers) in the PCB. At present, Jialichuang only accepts 1-6 layers of plates.

Plate type

FR-4 sheet

Plate type: board, half glass fiber, full glass fiber (FR-4), aluminum substrate, at present, Jialichuang only accept FR-4 plate.

Large size

40cm * 50cm

The size of the working board cut by Jialichuang is 40cm * 50cm. The PCB design size of customers is usually allowed to be within 38cm * 38cm. The specific size is subject to the document review.

Overall dimensional accuracy

+ / - 0.2 mm

Board shape tolerance ±0.2mm.

Plate thickness range

0.4 ~ 2.0 mm

Jia made at production thickness: 0.4/0.6/0.8/1.0/1.2/1.6/2.0 mm.

Plate thickness tolerance (T≥1.0mm)

± 10%

For example, plate thickness T=1.6mm, the real plate thickness is 1.44mm (T-1.6×10%) ~1.76mm (T+1.6×10%).

Plate thickness tolerance (T < 1.0mm)

+ / - 0.1 mm

For example, plate thickness T=0.8mm, the real plate thickness is 0.7mm (T-0.1) ~0.9mm (T+0.1).

Small line width

6mil

The line width should be greater than 6mil and no less than 6mil. As the picture on the right

Small gap

6mil

The gap should be larger than 6mil, and the minimum should not be less than 6mil. As the picture on the right

The outer layer of the finished product is thick copper

1oz~2oz (35um~70um)

Default conventional circuit board outer copper foil line thickness of 1oz, more can do 2oz (need to order remarks). As the picture on the right

The finished inner layer of copper is thick

0.5oz (17um)

The thickness of the copper foil line inside the circuit board is 0.5oz. As the picture on the right

Bore hole (mechanical drill)

0.3 ~ 6.3 mm

Small aperture 0.3mm, large aperture 6.3mm, if it is larger than 6.3mm, the factory needs to deal with it separately. Mechanical drill bit specifications are 0.05mm for the first order, such as 0.3mm, 0.35mm, 0.4mm... . As the picture on the right

Through hole single side welding ring

P 6 mil