I am looking for guidance and suggestions on my (very) basic tone() amplifier. Attached is my drawn schematic of how I currently intend to wire up my circuit. Here is my goal, driving factors, and key hardware:
Goal: Use a 8ohm 10W speaker from an old TV and the tone() function nto create a short (200ms), intermittent (once or twice a minute), loud beep when criteria in my code is met. My piezo buzzer was far too quiet.
- Simple: I'm just generating a short, single frequency tone. I don't want the complexity of an optimized, efficient, distortion free, audio amp. Its just not necessary. I intend to use the tone(); function.
- Reliable: The build utilizing this "speaker beeper" needs to be able to rely on this beeper working long term. I really don't want the speaker or electronics to burn out from inadequate design.
Key Hardware (not limited to):
- 5v logic from a Arduino Nano
- 12v lipo for driving the speaker (plenty of power)
- RLZ44N N-Channel MOSFETs
- 8ohm 10W speaker
Questions that I have:
- Is R1 even really required? If so, given 12v operation what spec resistor should I look for? Would a 10ohm 10W resistor be appropriate?
- Is diode D1 required for flyback damage prevention? If so, what specs should I look for in a diode for that purpose?
- Is capacitor C1 really required? If so, what spec capacitor should I look for? Is an aluminum electrolytic Low ESR capacitor suitable? That's what I have on hand.
- Is there anything else that should be changed to avoid damaging components?
If my true best option is to just go buy a cheap class A or D audio amp or something, then I can understand that. I'd of course rather use the components I have on hand if that can get the job done simply and reliably.
Its difficult sometimes to piece together the small details of a project like this when I'm teaching myself online. These forums and helpful people like you are a blessing. Thank you so much for your input, it is much appreciated!