Siren is a continuous tone that varies in frequency. Usually, the output of the siren circuit is very low which is hard to hear. Therefore, it is needed to build a circuit that can amplify and distribute the relatively low-volume siren tone produced by a siren circuit to a wider area through the speaker.
This project is about constructing a simple siren enhancer that can increase and boost the weak siren signal to an amplified 10 Watt signal. A bipolar junction NPN transistor and MOSFET are used for the amplifying purpose.
Hardware Components
For a detailed description of pinout, dimension features, and specifications download the datasheet of Siren Enhancer Circuit
| S.no | Component | Value | Qty |
|---|---|---|---|
| 1. | Battery | 9 to 12V | 1 |
| 2. | NPN transistor | 2N3904 | 1 |
| 3. | MOSFET | IRF9540 | 1 |
| 4. | Speaker | 8 Ohm/10 watt | 1 |
| 5. | Resistors | 1.2K, 330Ω | 1 |
IRF9540 Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of IRF9540
Siren Enhancer Circuit
Working Explanation
This siren enhancer circuit is the easy and simplest circuit with only four components. The circuit is ideal to use in a place where a loud output siren is required. The operating voltage of the circuit is 9 to 12V DC. The circuit uses the NPN 2N3904 transistor that amplifies the input audio signal from a siren generator circuit like UM66, UM3561, UM3481, etc. This amplified signal is then further amplified by an IRF9540 MOSFET, which enhances the audio siren signal to 10 watts. Any substitute MOSFET can be used in place of IRF9540. The IRF9540 transistor will become hot during operation therefore use a suitable heat sink is used with it. An 8-ohm speaker is used to get the amplified 10 Watt output.
Applications and Uses:
The circuit has many applications from the use in toys for children, automobiles, ambulances, fire stations, and security alarms in case of any emergency.
