A easy circuit for a white noise generator is a DIY electrical design that simulates the sound of static or hissing that you would hear when switching radio stations.
Applications for this noise include sound effects creation privacy sound masking and audio equipment testing.
The circuit takes use of the intrinsic electrical noise that exists in electronic parts.
Using a resistor or a reverse biased transistor junction are common methods.
To shape the properties of the noise, a capacitor can be used to filter out undesirable high or low frequencies.
Circuit Working:
Parts List:
| Component Type | Description | Quantity |
|---|---|---|
| Resistors | 6.8k, 1/4 watt | 1 |
| 68k, 1/4 watt | 1 | |
| Capacitors | 4.7μF, 50V | 1 |
| Semiconductors | Transistor BC547 | 1 |
| Zener diode 10V | 1 |
In this article, the circuit produces white noise by means of a BC547 transistor.
The first source of noise is an injection of current by a 10V zener diode that is put in reverse bias with the base of the transistor.
The zener diode is an essential component that is responsible for producing noise.
For the circuit to operate properly, the zener diodes polarity must be maintained.
To control the amount of current passing through the circuit, two resistors are used.
By removing undesired high or low frequencies, a 4.7uF capacitor filters the noise and shapes its features.
In order to generate a substantial amount of noise at the output, the circuit requires a rather high voltage in this case 24V.
A printed circuit board PCB can be used to build this circuit.
This entails connecting the electrical components to the appropriate pads after copying the circuit diagram onto the PCB using a particular technique.
Formulas:
You may build a simple circuit that uses transistor noise to produce white noise in order to make a white noise generator circuit.
Here are some essential and a simple formula for creating such a circuit:
Voltage Density of Noise:
An approximation of the noise voltage density Vd, en which the transistor generates, is as follows:
en = √4kBT * R * f
where,
- The Boltzmann constant (1.38 × 10−23 J/K) is represented by the symbol kB.
- Kelvin is represented by the symbol T.
- O is the unit of resistance R.
- The bandwidth expressed in hertz is f.
f typically spans a large bandwidth for white noise, producing a flat spectrum throughout frequencies.
Experimenting with component combinations and values is necessary to design an accurate white noise generator.
A simple noise generator circuit is formed by the resistors, zener diode and BC547 transistor, which has built-in noise characteristics.
To get the appropriate noise characteristics for your application, experiment with different resistor values and combinations.
How To Build:
To build a Simple White Noise Generator Circuit follow the below mentioned steps:
- Gather all the components mentioned in the above diagram.
- Connect collector of transistor Q1 to positive supply of +24V through resistor R1.
- Connect base of transistor Q1 to 10V zener diode.
- Connect emitter of transistor Q1 to ground.
- Connect resistor R2 between collector of Q1 transistor and 10V zener diode.
- Connect capacitor C1 from 10V zener diode to ground.
- Connect noise output between resistor R1 and collector of transistor Q1.
Safety Measures:
- It is crucial to remember that this specific design uses a greater voltage from 24V upto 26V, whereas other noise generating circuits work at lower voltages around 9V.
- It is best to put safety first and get advice from someone who has worked with greater voltages if you are new to electronics.
Conclusion:
This simple white noise generator circuit produces static like noise by using a zener diode and a transistor BC547.
To create the desired sound, the circuit amplifies and filters electrical noise from the component parts.
For optimal operation, a higher voltage of 24V to 26V is required.
If you want a clean design build it on a PCB but if you are not experienced with higher voltages proceed with caution.
References:
Understanding the circuit diagrams for white noise generators