Good day! Now we are going to assemble the low frequency amplifier. The TDA2004 microcircuit is taken as a basis.
It has two outputs, but the power of each separately is 8 watts, which is not so much. Therefore, we will use bridging. Such inclusion will increase the power by more than two times.
Amplifier characteristics
So, the main characteristics of our amplifier:- Supply voltage: 8-18 volts;
- Rated output power: 20 watts;
- Maximum output power: 25 watts.
Required details
- DD.1 - TDA2004;
- C1, C2, C3, C7, C8 - 0.1 μF;
- C4 - 470 μF, 25 Volts;
- C5 - 10 μF;
- C6 - 1 nF;
- R1 - 470 Ohm;
- R2, R3 - 22 ohms.
Printed circuit board
For a printed circuit board, we need a piece of PCB 3x2 cm in size, as well as a drawing of the board:(Downloads: 133)
Making a low frequency amplifier
Cut and transfer by laser-ironing method. Anything that is not fully transferred, we finish painting with varnish.
We will etch in a solution of hydrogen peroxide and citric acid. Pour three tablespoons of peroxide into a large disposable glass, pour a tablespoon of citric acid and add a pinch of common salt, it is a catalyst and is not consumed during the reaction. Stir the solution until the substances are completely dissolved and throw the board there. Bubbles of hydrogen begin to evolve, and the solution turns blue.
The board is etched for about half an hour. You can speed up the process a little by placing the solution in the sun.
When the excess copper dissolves, we take out the board and rinse it with water.
The used solution should be poured into the general sewer.
Next, we clean the board from the toner with acetone and tin the tracks.
First, we solder the microcircuit in its place, then the rest of the components.
Make the installation, focusing on the picture:
At this stage, the amplifier is ready. Before turning on, the microcircuit should be installed on the heatsink.
This is a compact but rather powerful amplifier. I connected a 25 W 4 Ohm low-frequency head to it - I did it perfectly, at full volume no wheezing, clicks and other sound distortions were observed. For an hour of operation, the radiator warmed up to 60 degrees.
And on this my article came to an end, good luck to everyone in repetition!
