Did anyone tried to listen a radio but heard too much noise? which was hard to hear, right?
So our this problem brings a solution through this Noise Limiter Circuit which tell us how to make small circuit which helps remove noise and makes radio sound better.
Also, the circuit uses transistors like tiny switch to stop bad noise.
WARNING: Making electronics are not safe always, so try only if anyone is having expert person around.
What is Noise Limiter Circuit:
This electric circuit help make input signal clean, which remove noise if noise goes over certain level like from air or some other things.
Now we will talk how to make this noise limiter circuit and how it will work.
Circuit Working:
Parts List:
| Components | Values | Quantity |
|---|---|---|
| Resistors | 4.7k CFR 1/4 W | 1 |
| 1MEG CFR 1/4 W | 1 | |
| Potentiometer 10k | 2 | |
| Capacitors | Electrolytic 10µF 25V | 3 |
| Semiconductors | Transistor BC547 | 1 |
| Diodes 1N4148 | 2 |
Circuit Details:
To begin with , the circuit uses a smart design to reduce noise without affecting the radio signal quality.
Signal and noise connect together to amplifier Q1 so we need potentiometer R3 for this to work right.
How Amplifier Work:
Signal and noise come in same way and transistor Q1 make them bigger to amplify and when signal gets strong it is easy to find and use.
But diodes D1 and D2 stop the signal from getting too big, so they keep output change small with around 1.2V so it does not jump too much.
Formulas:
Noise Limiter Circuit Formulas:
Formula 1:
Peak to Peak Output Fluctuation Limit:
Vpplimit = 1.2V
here
- Vpp mean voltage from top to bottom means highest positive (Vpeak+) minus lowest negative (Vpeak–) in one wave.
- Limit mean max value Vpp can go but is not more than that.
This formula say circuit output from peak to peak (Vpp) and must stay under 1.2V; and if Vpp connects more than 1.2V maybe circuit will not work good.
Control Output Signal:
We can turn potentiometer R3 slowly and make signal stay in good level but bery important is that noise must not be bigger than signal output.
Formula 2:
Signal Output Adjustment:
Vsignal = Vpplimit
here,
- Vpplimit is the peak-to-peak voltage we allow in this circuit.
- Vsignal is what we want the signal to be as same as Vpplimit if everything work perfect.
Result:
When Vsignal = Vpplimit the signal stays within the safe limit and does not go beyond it, but however, if the signal exceeds the limit, the circuit cuts or clips the signal, which is not good.
Actual value of Vsignal depend on circuit setup and how we measure it.
How to Build:
To build a Noise Limiter Circuit below are the connection steps:
- First, collect all parts we need like resistors, transistors, diodes and potentiometers.
- After that, follow the circuit diagram and put parts on prototype board or PCB and then connect them same like in design.
- Before we give the input signal, make sure the circuit has proper grounding.
- Also, use potentiometer R3 to control how signal and noise connect together to amplifier Q1.
- Then turn R3 slowly and adjust until signal output reaches the target level of 1.2V.
- Next, watch the broadcast signal and check if noise is small and under control and if needed change circuit a little to make it work better.
Conclusion:
To conclude, people who love electronics or engineers can use this Noise Limiter Circuit; which also help make weak radio signals sound much better if we build it like the above steps.