| 摘要 |
Several oscillator units are on a main circuit board, each having its own test seating for individual testing of the units. The positive voltage and earthing circuit patterns (VCC,GND) and signal regulating circuit patterns (VT) of each single oscillator unit is electrically connected with all oscillator units. With through holes (139) located on main board at location where inner surfaces of each through hole is coated with conductive material. Each oscillator is fed power from the main circuit board. The main circuit board (10) has an insulation layer with a copper sheet layer (11,12) on the upper side or under side. A second insulating layer (15) of the same thickness as the first layer and a copper sheet layer (13) are laid on each other and attached to the circuit board. Providing a main circuit board with three copper sheet layers. The upper copper sheet layer (13) is used to form several component circuit patterns for the oscillator units. The middle copper sheet layer 11 is used to form several current and earthing circuit patterns, and signal circuit pattern, the lower copper sheet layer (12) is used to provide a common earthing circuit pattern for the oscillator units. After the electronic components are soldered to the main circuit board, the main circuit board is etched to define the area of each oscillator unit. The etching knife used has a V-shaped blade and is used so that the middle copper sheet layer is not cut. It provides a number of V shaped etches ridges (14) on the upper surfaces of the main circuit boar. Only the upper and lower copper sheet layers are cut, so each single oscillator unit is insulated from the others and is separated from the main circuit board |
