Here we design a simple “Volume Level Indicator” using transistors, this circuit included a condenser mic to receive the audio or sound and makes the LED glow according to the sound level and power.
The working principle of a volume level indicator using a transistor circuit is as same as a VU meter (A volume unit (VU) meter or standard volume indicator (SVI) is a device displaying a representation of the signal level in audio equipment). It can help us from any inconvenience by avoiding load sound distortion and noise and making it easy to determine sound levels. If the audio signal is connected directly to the circuit in the place of any microphone, it can directly detect the sound level from the audio signal.
Hardware Component
The following components are required to make Volume Level Indicator Circuit
| S.no | Component | Value | Qty |
|---|---|---|---|
| 1. | NPN Transistor | BC547 | 5 |
| 2. | Condenser Mic | – | 1 |
| 3. | Resistor | 1KΩ, 10KΩ, 1MΩ | 4, 2, 1 |
| 4. | Ceramic Capacitor | 0.1µF | 1 |
| 5. | LED | – | 4 |
| 6. | Connecting Wire | – | – |
| 7. | Battery | 9V | 1 |
BC547 Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of BC547
Volume Level Indicator Circuit
Working Explanation
Here is circuit is based on transistors. We used the BC547 transistor, it is an active device termed an NPN transistor with three terminals, Collector, Base, and Emitter. These transistors drive LEDs depending on the volume level. Each transistor receives input at the base terminal and all emitter terminals are coupled to the ground supply through a resistor. Now the first Stage in this circuit is a sound receiver by condenser mic and then the Q1 transistor receives an audio signal from the mic and drives Q2 – Q5 transistors depending on the sound level. Here each LED glows when the connected transistor gets the signal. This circuit Indicates different volume levels through stages of LEDs.
Applications
- Can be used in places such as factories, manufacturing complexes, apartments & homes
- An important part of wide-scale industrial processes such as cooling tower water level control, life station switches, tsunami warning systems, irrigation control, and fuel tank level gauging & sump pumps.
