lm386_amplifier
Title: Build an LM386 Amplifier
Class Size: 5
Cost: $20 (estimated)
Pre-requisites: none
Minimum Age: XX and up (under 18 must have parent present)
Learn to solder an LM386 amplifier.
Order of Build:
- Resistors
- 1K (brown-black-red)
- 4.7k (yellow-violet-red)
- IC socket
- Orientation isn't critical, but should be observed
- Note that pin 7 doesn't have a solder pad. No need to solder it.
- Ceramic capacitors (C1 & C4, both 0.1 uF)
- No orientation
- 3.5mm jack
- External connection pins
- A+/A- (audio input?)
- +/- (power) (if using a 9V clip, just solder the clip directly instead of pins, but you'll want to hot glue some strain relief because it will fail eventually, otherwise)
- S+/S- (speaker)
- Cut the pairs of pins off of the 6-pin strip
- Solder in one pin, adjust fit if necessary, and then solder in the other.
- LED (D1)
- Long lead toward the triangle, short lead toward the line
- Power jack (J3)
- Solder one pin, adjust, solder the other two
- It may be in your best interests to insert the LM386 into the IC socket at this point. The caps & pot make it difficult to insert if present.
- Electrolytic capacitors
- Long lead positive.
- Potentiometer
- Cut off the anti-rotation tab
- Solder one pin, adjust, solder the other two.
- Speaker
- Use two headered wires. cut off headers at one end, and strip the remainder
- Solder stripped wires to tabs on speaker
- Insert header pins into S+ & S-
Options/Hacks:
- External speaker (i.e. a cabinet or something)
- Wire up header wires to a 1/4“ jack instead of the speaker
- Additional gain
- Simple way: wire up a capacitor between pins 1 & 8 of the LM386
- adjustable way: wire up a 5k potentiometer between pins 1 & 8
- Power switch
- Wire up SPST switch between power source and + on PCB
lm386_amplifier.txt · Last modified: 2017/12/02 20:05 by sdh7