confounded
New Member
Hi, i thought i'd experiment with a couple of lm386 op amps and build a footstep detector by connecting 1 to a speaker from my hifi then the other to that op amp as shown in my pathetic diagram!
when i put just 1 to the speaker it was fine, i detected voltage change when tapping the floor near speaker about 50mv max on top of aprox 3.8v dc
But when i connect the next op amp to it and turn on power the speaker makes a noise. Can someone please tell me why its making a noise?
I have 200 gain in op amp 1 and 20 gain in op amp 2. I am using a 9v battery. The speaker has impedance of 6 Ω. I hope i have supplied all necessary information for you guys.
when i put just 1 to the speaker it was fine, i detected voltage change when tapping the floor near speaker about 50mv max on top of aprox 3.8v dc
But when i connect the next op amp to it and turn on power the speaker makes a noise. Can someone please tell me why its making a noise?
I have 200 gain in op amp 1 and 20 gain in op amp 2. I am using a 9v battery. The speaker has impedance of 6 Ω. I hope i have supplied all necessary information for you guys.