A multi-tone generator is often called a signal generator. A tone generator circuit is a simple electronic circuit, which has wide applications in different domains. The circuit below generally creates different levels of sound frequencies by electrical means. The term multi-tone in the name depicts the working behavior of the circuit. It amplifies the output at diverse desired levels known as tones.
The key element to the multi-tone generator is the 2N2646 transistor. 2N2646 is a three terminals unijunction transistor that is widely known as an electrically controlled switch. It ideally uses oscillators, sensors, SCRs triggering circuits, timers, etc. Henceforth, the transistor in this circuit with a minimum list of components gives the best result as a tone generator.
Hardware Components
The following components are required to make Multi-Tone Generator Circuit
| S.no | Component | Value | Qty |
|---|---|---|---|
| 1. | Breadboard | – | 1 |
| 2. | Connecting Wires | – | 1 |
| 3. | Battery | 9v | 1 |
| 4. | Transistor | 2N3904, 2N2646 | 1 |
| 5. | Push Button | – | 3 |
| 6. | Variable Resistor | 100k | 3 |
| 7. | Resistor | 470, 47 ohm | 1, 1 |
| 8. | Ceramic Capacitor | 100nF | 1 |
| 9. | Speaker | 8 ohm | 1 |
2N3904 Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of 2N3904
2N2646 Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of 2N2646
Multi-Tone Generator Circuit
Working Explanation
The above circuit works as a tone generator. Three 100KΩ variable resistors generate different levels of tones; however, the 100nF capacitor helps in increasing and decreasing the frequencies of the oscillator. The Q2 transistor contributes to the amplification of the signal that uses for an 8Ω speaker at the output.
Applications & Uses
- A tone generator is most commonly served in musical instruments
- It is also used for fault detection in the probes of cable televisions
- Pest controlling device uses a tone generator to generate a frequency that repels the pest
- The tone generator is also used for recording music in a soundproof room
