Transmit and Receive Morse Code Using Light With Arduino and Smartphone's CameraView Instructable »
My favorite probably with TDA2822M, it is the first amplifaier I've build using IC.
The light bulb is needed, it limits current, without it something definitely will go wrong. In theory, you can use a DC power supply that can limit its current, but such power supply also should not have capacitors connected on its output... well I've never seen something like it, so the lightbulb is probably the best what you can use here.It is great if someone will improve the circuit, but frankly speaking, I don't know what else can be improved here. Next step is to use more transistor.
Well, I am not good at explanations, but I can try. The light bulb charges the capacitor C2, and the MOSFET discharges it. When C2 charges the current flows through it in one direction and when it discharges the current flows in another direction. C2 is connected sequentially with the speaker, so the current flows through the speaker as well and it makes sound... this explanation assumes that you know what MOSFET does. Suggestion for beginners: replace MOSFET and the light bulb with push-buttons (but never push them at the same time, otherwise it will be short circuit) press one button and then press another, and look how diaphragm moves, and in which direction. it should at least help to understand how it works.
I think there is no need for more powerful MOSFETs, IFR540N will probably handle even 100W light bulb, I think it is not reasonable to go beyond that. A good heat sink is important here.
I got it now, your phone does not recognize this device for some reason... try adding for example 100 Ohms resistors after the audio jack, between ground and right channel and between ground and left channel... I think that maybe your phone needs some real load, that is why I suggest adding resistors. You need to make your phone recognize the audio jack as a device. You did everything correct, but your phone thinks that nothing is connected.
Hi, The circuit is Ok, it should work. How does it behave when you connect it to the power? First, make one channel work, and then add another channel. When you connect this circuit to power the light bulb should turn on (if it doesn't, test your light bulb, if the bulb is OK, then MOSFET is probably dead.)If light bulb turns on after you connect the power then test your MOSFET more: Connect a piece of wire between "gate" and "source" (labeled as "G" and "S" on the circuit). After connecting the wire, the light bulb should turn off. If it doesn't turn off it means MOSFET is dead. Need more information to tell more...
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