30 Watt FM Linear amplifier with Mosfet BLF245

  
The achievement of this 30 watt amp was thought to take place on a heatsink microprocessor PC. Equipped with its fans, the advantage of this method of cooling was chosen for the fact it is common and not very expensive. The size of the printed circuit will adapt quite easily to the type of sink that you have available, nine if possible, because often, those of recovery, the fans have already lived and the price of a new model remains very affordable. The amplification mode is class AB. Below is a description of the mounting frame. Ground planes are made of carnations, but it is also possible to achieve with simple crossings `legs of resistors,` for example .. The circuit will be constructed from glass epoxy double-sided, 0.8 mm thick. The dimensions of the circuit must be respected at best, due to the presence of lines granted `strip-line. These dimensions are 73 mm wide and 63 mm in height.
30 Watt FM Linear amplifier with Mosfet BLF245 - schematic

It is preferable to make the holes and threads of the sink before starting to wire the map. The holes correspond to the four struts holding the PCB and the two central holes in the fixing of the transistor. The heatsink and printed circuit board is assembled with a few slices to ensure the height relative to the fixing of the transistor. In my case, four rounds were necessary. The threads are boring M3.Apr├Ęs format, check that the holes overlap and are centered. Pre-installation, installation of rivets. To do this, I use a needle and a hammer, no special tools! After installation, I run the weld duplex. The rivets can be replaced by bushings "legs of resistance" welded on both sides, the result will be the same! The rivets and welding applied! That's what it gives the copper side, we need a soldering iron hot and powerful! The placement of SMD components. Start with the resistors and capacitors, diodes and then finish by chemical and potentiometer adjustable so that the few crossings "+28 V, the RF output. For better stabilized circuit for setting CMS, attach it to the sink, the whole move less! From now on, you can ask the BLF245, start with the set with two M3 screws after putting the thermal paste and tighten moderately. Do not take the wrong direction, the beveled side "drain" on the side of the capacity output. Do not forget precisely this ability! Finish by laying the coils, toroid...



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