Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Small Microphone/Speaker Circuit

Status
Not open for further replies.
Sorry for dragging it on, but I'm still a bit sketchy on some of em-
As the first 470uF is a bypass cap, it could technically be placed somewhere else, right?
Can you elaborate on what the 100uF does? What precisely is this "feedback"?
Out of pin 5, am I right in thinking no DC current can pass through the 470uF cap to the speaker?
 
bluethecow said:
As the first 470uF is a bypass cap, it could technically be placed somewhere else, right?
No. It belongs across the battery.

Can you elaborate on what the 100uF does?
The 100uF cap smooths and filters sounds from the supply for the microphone so that they don't cause feedback.

What precisely is this "feedback"?
Feedback is output that gets into the input. If it is positive feedback then oscillation will occur. If it is negative feedback then amplification is reduced.

Out of pin 5, am I right in thinking no DC current can pass through the 470uF cap to the speaker?
Correct. A capacitor passes AC but blocks DC.
The output of the LM386 is about 4.5VDC when the circuit has a 9V battery. If the capacitor wasn't there then the 4.5V across the 8 ohm speaker would cause a DC current of 4.5V/8= 563mA which would quickly kill a 9V battery and cause the speaker's cone to be offset.
 
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top