An amplifier is an electronic device that increases the voltage, current, or power of a signal. Amplifiers are used in wireless communications and broadcasting, and in audio equipment of all kinds. They can be categorized as either weak-signal amplifiers or power amplifiers. Weak-signal amplifiers are used primarily in wireless receivers. They are also employed in acoustic pickups, audio tape players, and compact disc players. A weak-signal amplifier is designed to deal with exceedingly small input signals, in some cases measuring only a few nanovolts (units of 10-9 volts).
Such amplifiers must generate minimal internal noise while increasing the signal voltage by a large factor. Power amplifiers are used in wireless transmitters, broadcast transmitters, and hi-fi audio equipment. The most frequently-used device for power amplification is the bipolar transistor. As the timer, IC555 has many applications as timer circuits, alarm circuits, wave generators, etc.., But for a change here we design a simple amplifier based on IC 555.
Hardware Require
| S.no | Component | Value | Qty |
|---|---|---|---|
| 1. | IC | NE555 Timer | 1 |
| 2. | Loudspeaker | 8Ω | 1 |
| 3. | Condenser Mic | – | 1 |
| 4. | Transistor | BC547 | 1 |
| 5. | Resistor | 47KΩ,680KΩ,100KΩ,1KΩ,10KΩ | Each One |
| 6. | Capacitor | 0.1uF,1uF,1 nF,10uF | Each One |
| 7. | Battery | 15V | 1 |
| 8. | Connecting Wires | – | – |
Circuit Diagram
Working Explanation
As shown in the circuit, first the condenser mic is biased with the supply through the 47KΩ resistor and output taken from the mic. As you will only receive mV range output, so it needs to be preamplified. Here the BC547 NPN transistor acts as a preamplifier and the output is connected with the control terminal (Pin5), so IC555 gives modified PWM output depending on input from the mic. And connecting the loudspeaker at the output terminal (pin3) gives an amplified sound. Here the IC555 can amplify the input signal without any phase inversion, to achieve amplification make the connections as per the circuit diagram.
Applications
- In sound systems, these amplifiers are the most widely used.
- In radio signal broadcasting these amplifiers are used.
- The signal transmission for long-distance communication is the most amplifier that is utilized.
