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Speaker Protection board


1. 1×12V 30A relay
2. 2×C945F Transistor.
3. 1×C9013 Transistor.
4. 2×220uF capacitor 50/63V.
5. 1×1000uF capacitor 25V.
6. 1×680Ω resistor 1/4w.
7. 1×1kΩ resistor 1/4w.
8. 1×2.7kΩ resistor 1/4w.
9. 1×3.3kΩ resistor 1/4w.
10. 3×10kΩ resistor 1/4w.
11. 1×33kΩ resistor 1/4w.
12. 9×1N4007 diode.
13. 1×2 pin screw terminal.
14. 4×battery terminal.
15. 1×100k preset/ variable resistor.
16. 1×L7812+V regulator.
17. 2×3mm Led.

watch this video for better understanding
In this post I make a speaker protection board. Which can handle upto 30 ampere Load. You can use this board upto 2000 watts amplifier. This circuit is powered by 12 volts. If this circuit is connected to the amplifier output, and if the transistor burns out, this circuit will not allow current to flow through the speaker.

License► ©Technical Mriganka. You can't use this pcb layout for commercial purpose. You can use this pcb layout only for educational and diy projects.

How to make pcb by ironing mathod► 
For make pcb you need pcb layout. download the pcb layout and print it by laser printer on photo paper. Then cut the pcb layout. Then press the pcb layout by iron on copper clad board. Press the iron 10-15 munites. Then leave the pcb for cool down 10 munites. when the pcb was cool, put the pcb in water and move the pcb layout to copper clad board. Then put the pcb in ferric chloride [FeCl3+H2O] for etching 10-15 munites. when etching was end, clean the pcb by water. Then make hole on pcb. And then press the upper side print of pcb. Now your pcb is ready mount components by instruction.

How to test this speaker Protection board►
After Complete The Board. connect this board to 0-12V transformer. and connect the transformer with series lamp. 
For test this speaker Protection board. Touch amplifier's main voltage wire (+v and -v) to speaker protection's input. If the relay cutout the voltage and the red led is turn off, then the speaker Protection is ok.

Post a Comment


  1. Hello there,

    Do you have Gebers or a Sprint Lay6 file you can share?

    Thank you,


  2. hello,for short circuit output works?