This circuit is a simple intercom circuit based on LM386 low voltage audio amplifier. It uses 8 ohm speakers that works as a microphone and as speaker at the same time. A 10k potentiometer is used to adjust the volume. It also has a double pole double throw switch that is used as push to talk switch.
Simple two way intercom – [Link]
user drj113 on Instructables writes:
This Instructable will show you how to make your own original stylophone – The schematic that this is based on is my own, so it is free from Intellectual property restrictions. It is based around a 555 timer (so it could be an extension of the recent “Know Your 555 timer” article), and uses an ubiquitous LM386 audio amp so it can have enough volume to stand out from the crowd. [via]
DIY Good old fashioned stylophone – [Link]
Ruby is a battery-powered amplifier and it is an “enhanced” version of the Little Gem. This amplifier is based on LM386 chip and has an input buffer that is feeding the inverting input. The input buffer helps to retain treble detail going into the 386 chip. It is powered from a single 9V battery. Check schematic and construction details on the link below.
Ruby : A battery-powered amplifier – [Link]
The LM386 IC is a low voltage power amplifier. The gain is set to 20 but can be changed from 20 to 200 using external components. The basic setup is really simple using only a few components as shown on the schematic above.
Audio Power Amplifier using LM386 - [Link]
This project shows how to build an audio amplifier inside a Altoids tin box. The speaker, circuitry, AA battery and 3.5mm connector are fit inside the tin. Power is supplied by a Maxim MAX756 Step-Up DC-DC Converter and amplification is done with an LM386 op-amp chip. Follow instructions on the link below.
Altoids Tin Speaker – [Link]
The Tiny Audio Amplifier kit is a good choice for battery operation. It is based on LM386 IC.
- Power supply – 6 – 12 VDC
- Output power – 1 W, 8 Ohm
- The quiescent power drain is only 24 mW when operating from 6 VDC
- Self-centering output quiescent voltage
- Onboard PRESET to adjust volume
- Terminal pins for connecting power supply, audio signal and speaker
- Power-On LED indicator
- ON/OFF PCB mounted slide switch for power supply
- Four mounting holes of 3.2 mm each
- PCB dimensions 44 mm x 44 mm
Tiny audio amplifier using LM386 - [Link]