If we want to make sound generator circuit for cheap? then this post for Simple Universal Signal Generator Circuit show easy way to build using transistors.
These type of circuits are also good for:
- Fixing broken radio or amplifier.
- Testing our other electronic project.
- Learning how electronic make sound.
Also, we can make this circuit at a very low cost.
What is a Universal Signal Generator Circuit:
Universal Signal Generator circuit is helpful tool for testing and fixing electronic circuits, which can make different kind of electrical signals.
Also, not like special signal generator for only one job but this circuit can make many type of signal;, so it is useful for engineer, technician and people who like electronics.
Circuit Working:
Parts List:
| Components | Values | Quantity |
|---|---|---|
| Resistor | 5.6k 1/4 W CFR | 1 |
| Potentiometers 2M, 2k | 1 each | |
| Capacitors | Ceramic 0.0022µF | 1 |
| Ceramic 0.022µF | 1 | |
| Semiconductors | Transistors BC547, BC557 | 1 each |
| Battery 9V | 1 |
This is an easy circuit diagram with short explanation of how transistor audio signal generator works:
First, transistors Q1 and Q2 work as amplifiers and generate as well as boost the audio signal.
Then control knob R2 changes the sound frequency or tone and by turning R2 change resistance so tone also changes.
After that, another control knob R3 adjust the signal strength like amplitude.
Also, capacitor C1 and C2 help pass only AC audio signal as they block DC; hence, Q2 and C2 gives the final output of the signal.
Formulas:
By using parts in this circuit we can make astable multivibrator or oscillator which become universal signal generator.
Also, this circuit can make many kind of signals like pulse and square wave so it is good for testing and signal making.
Frequency Formula:
Astable multivibrator gives frequency like this:
f = 1.44 / (R1 + 2 * R2) * C
where:
- R1 is resistor going to base of NPN transistor BC557.
- R2 is resistor from NPN collector to base of PNP transistor BC547.
- C is total of capacitor C1 and C2 used for timing.
Hence, change the potentiometer and we can change the frequency, so this simple circuit can make square wave at different speed.
How to Build:
The build a Simple Universal Signal Generator Circuit follow the below connections steps:
- First, collect all parts and tools we need, then think where to put the transistors inside small box for best working.
- Also, put control knobs R2 and R3 in right place on circuit board.
- Then add all other parts carefully and follow steps correct for good circuit building.
- After placing all the parts, build the complete circuit inside a small metal box.
- Next, check all wire and part connection to ensure there is no mistake.
- After finish, turn ON the signal generator and see if it works.
- Here, R2 control the sound frequency or tone and R3 control how strong the signal is.
- Also, to be sure it works right compare the output signal with known good one like another signal generator.
- Finally, if something is different then change and fix it.
Testing and Changing:
- When building follow correct wiring like in the circuit diagram.
- To get sound or tone we want turn ON the circuit and adjust R2.
- To make sound louder or softer adjust R3.
- To make circuit more perfect compare output with real trusted source and adjust as needed.
Note:
- This is just simple guide an exact part values can change for our need, also we must calculate values depending on what frequency we want and how we use it.
Conclusion:
To conclude, people use the Simple Universal Signal Generator Circuit in many areas such as telecommunication work, audio testing, electronics, learning and research, schools and laboratories.
Moreover, it is helpful tool for people working with electronics and it can also make many kind of signals and help test or check circuits.