LM358 microphone amplifier – Direct connection of the Microphones does not give the power audio signals. it should be like very small sound.
so we neds to boost that signals, so I’m decided to build a small microphone amplifier circuit. This circuit is based on the Lm358 op-amp.
Pinout of this operational amplifier ic is:
| PIN NO | DESCRIPTION |
| 1 | (Output 1) – This is the output pin of op-amp 1 |
| 2 | (Input -) – This is the inverting input of op-amp 1 |
| 3 | (Input+) – This is the non-inverting pin of op-amp 1 |
| 4 | (GND) – Ground connection or negative supply input pin |
| 5 | (Input2+) – The non-inverting input of the Op-amp 2 |
| 6 | (Input-) – The inverting input of op-amp 2 |
| 7 | (Output2) – The output pin of op-amp 2 |
| 8 | (Vcc) – positive supply voltage pin |
LM358 microphone amplifier circuit diagram
Components required
| Component name | Quantity |
| Lm358A op-amp ic | 1 |
| Mic | 1 |
| 10k 1/4 watt resistor | 3 |
| 1k 1/4 watt resistor | 1 |
| 100k 1/4 watt resistor | 1 |
| 10uf/25v capacitor | 1 |
| 220uf/25v capacitor | 1 |
| 100nf capacitor | 1 |
