Construct a 9V Siren

This project provides the schematic and the parts list needed to construct a very simple Siren. This project will help beginners to electronics understand one of the application of operational amplifers(OP AMP). In this case, the LM 358 operational amplifier is configured as a VCO(Voltage Controlled Oscillator).

General Description of LM358

The LM158 series consists of two independent, high gain,internally frequency compensated operational amplifiers which were designed specifically to operate from a single power supply over a wide range of voltages. Operation from split power supplies is also possible and the low power supply current drain is independent of the magnitude of the power supply voltage.

Application areas include transducer amplifiers, dc gain blocks and all the conventional op amp circuits which now can be more easily implemented in single power supply systems. For example, the LM158 series can be directly operated off of the standard +5V power supply voltage which is used in digital systems and will easily provide the required interface electronics without requiring the additional �15V power supplies.

Unique Characteristics

a) In the linear mode the input common-mode voltage range includes ground and the output voltage can also swing to ground, even though operated from only a single power supply voltage.
b) The unity gain cross frequency is temperature compensated.
c) The input bias current is also temperature compensated.

Advantages

a) Two internally compensated op amps
b) Eliminates need for dual supplies
c) Allows direct sensing near GND and VOUT also goes to GND
d) Compatible with all forms of logic
e) Power drain suitable for battery operation

Features

a) Internally frequency compensated for unity gain
b) Large dc voltage gain: 100 dB
c) Wide bandwidth (unity gain): 1 MHz (temperature compensated)
d) Wide power supply range:
� Single supply: 3V to 32V
� or dual supplies: �1.5V to �16V
e) Very low supply current drain (500 �A)�essentially independent of supply voltage
f) Low input offset voltage: 2 mV
g) Input common-mode voltage range includes ground
i) Differential input voltage range equal to the power supply voltage
j) Large output voltage swing: 0V to V+- 1.5V

This powerful siren can be used as a final building block in an alarm circuit by using a relay to activate or deactivate it.

You can find the CK1207 9V Siren kit here under the AUDIO AND MUSICAL category.