If you do not have a scope you can get Zeitnitz freebe which turns yourThanks Dana - sorry I don't yet have a scope.
Is this what's called a closed loop circuit to more accurately control the gain of the amplifier?
In your view should this circuit work? I don't want to spend any more time trying to rewire if it is suspect in your opinion.
Many thanks
Alistair
Every IC manufacturer provides selection tools, applicatiin notes ... for free. So do the distributors, too.can you please give me any pointers to find a "more modern circuit"?
Did a LM386 overheat ?
In your schematic above you are directly loading output with 1000 uF,
curious why ?
Datasheet typical application shows -
View attachment 167871
If you are seeking higher power there are many solutions out there -
Tales From the Chip: LM386 Audio Amplifier
Tales From the Chip: LM386 Audio Amplifier: Audio is one of the most entertaining, time-consuming and (eventually) wallet-draining ways of learning about and falling in love with electronics. Reproducing, recording and amplifying audio gets you up close and personal with the electrons rocketi…www.instructables.com
A scope is key to make sure your layout is not osillating, that could have burned out one of the LM386's,
and its oscillation above audio freq so you never heard anything.
Noisy LM386 based audio amplifier
remember to keep the remember to keep the capacitor’s legs as short as possible, that also helps.www.robotshop.com
LM386 Instability Issue
Hi all. A while ago I started looking into designing a heterodyne bat detector circuit. I posted a thread on here to ask for advice. So for reference you can find this thread here: http://www.electro-tech-online.com/threads/ultrasound-transducer-for-bat-detector-project.126293/page-2 Since...www.electro-tech-online.com
Also not all bypass caps, for the same C, are as effective in their ESR performance -
View attachment 167873
Regards, Dana.
Dana's bridged LM386 amplifiers in post #2 almost overheats the low power LM386 amplifiers.
1) A graph in the datasheet shows with a 6V supply and an 8 ohms speaker, the output with low distortion is 0.2W which is 3.6V p-p.
Another graph shows the max p-p output is 4V. 3.6V/4V= 0.9 times.
With a 9V supply, the max p-p output is 6V so with low distortion it will be 6V x 0.9= 5.4V p-p which is 0.46W into 8 ohms.
Another graph shows that the dissipation (heating) is 0.55W when its output is 0.46W.
Bridging doubles the p-p voltage, current and losses. The 8 ohm speaker appears to be 4 ohms.
A graph shows that with a 12V supply and a 4 ohm load, the max p-p output is 3.5V so with low distortion will be 3.5V x 0.9= 3.15V p-p which is 0.31W into 4 ohms. The heating is 1.2W. Then the bridged low distortion output onto 8 ohms is 1.24W and the total heating is 2.4W(close to its max allowed heating).
With a 9V supply the bridged low distortion output into 8 ohms is also 1.24W and the heating is only 1.6W.
The distortion, bridge circuit, 9.3% for 9V supply, 7.3% for 12V supply, from sim.Without bridging, with a 9V supply and an 8 ohm load the distortion should be fairly low.
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