Simple Universal Signal Generator Circuit

Looking for a cheap way to build a sound generator circuit to test your electronics projects?

This post shows how to make a simple one using transistors which is perfect for:

• Fixing broken radios or amplifiers.
• Testing other electronics projects.
• Learning about how electronics make sound.

One can design this circuit at a much lower price.

What is a Universal Signal Generator Circuit:

A helpful electronic test tool for testing and troubleshooting electronic circuits is a Universal Signal Generator circuit which can produce various kinds of electrical waveforms.

Compared to specialized signal generators made for particular purposes this circuit can create a wide range of signals making it useful for engineers, technicians and electronics fans.

Circuit Working:

Parts List:

Here is a simple circuit schematic and brief description of the transistorized audio signal generators working:

Two transistors Q1 and Q2 are used in the circuit as amplifiers.

The audio signal is generated and amplified by these transistors.

The control potentiometer R2 is in charge of modifying the audio frequency or output tone.

The tone gets changed by turning R2 which changes the circuits resistance.

By acting as a level adjustment pot the control potentiometer R3 lets one regulate the output signals amplitude or strength.

Coupling capacitors C1 and C2 ensure that only the AC audio signal is transferred by preventing any DC components from entering the circuit.

The connection of Q2 and C2 provides the final output.

Formulas:

Using the components from the following circuit an astable multivibrator or oscillator circuit is created to give a universal signal generating circuit.

Because it can generate a range of signals including pulses and square waves this type of circuit is useful for signal production and testing.

Calculation of Frequency:

An astable multivibrators frequency f is roughly provided by:

f = 1.44​ / (R1+2 * R2) * C

where,

• The resistor R1 is connected to the NPN transistors base BC557.
• R2 is the resistor that connects the NPN transistors collector to the base of the PNP transistor BC547.
• C represents the capacitance (sum of C1 and C2) used in the timing network.

By varying the potentiometers the output of this simple signal generator circuit is set to produce a square wave at a required frequency.

How to Build:

The circuit construction rules for the Simple Universal Signal Generator Circuit are provided below:

• Start by assembling all required circuits equipment and parts.
• Decide where the transistors should be placed within the little box to provide the best performance.
• Place the control potentiometers R2 and R3 on the circuit board at the right spots.
• Add more parts carefully based according to the given instructions for accurate construction.
• Put all of the parts in place then assemble the circuit within the little metal mini box.
• To rule out any possible mistakes verify the connections.
• After assembly turn on the signal generator and check that it functions as designed.
• R2 is used to fine tune the audio frequency or output tone and R3 is used to modify the signal intensity.
• For complete accuracy and dependability compare the signal generators output to the one of a trusted source such as a similar generator.
• Based on the equivalent results make any changes that are needed.

Testing and Modification:

• Make sure you follow the right connections while assembling the circuit to comply with the given schematic.
• To get the desired tone or audio frequency turn on the circuit and modify potentiometer R2.
• To regulate the signals loudness and level change potentiometer R3.
• To ensure accuracy and dependability fine tune the circuit by comparing its output to a confirmed source.

Note:

This is only a simple description the exact values of the components may differ based on ones particular needs.

Calculating component values depending on chosen frequency range and other requirements is important.

Conclusion:

Applications for Universal Signal Generator circuits are usually found in a number of fields such as telecommunications, audio testing, electronics research and development and educational environments.

They are useful instruments for anybody dealing with electronic circuits because of their versatility and wide range of skills which allows them to mimic and analyze various kinds of signals.

References:

Design of a Powerful Signal Generator Output Stage