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Md Jony Islam Author
Md Jony Islam
CalculatorToolsProjectExpert
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Małgorzata Koperska, MD Steven Wooding
Last updated: September 24, 2025

Single Transistor Mosquito Repeller Circuit Using BC547C

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BC547 Transistor

BC547 Transistor

General-purpose NPN bipolar junction transistor (BJT)

104PF Capacitor

104PF Capacitor

Medium-value film or ceramic capacitor for AC/DC circuits

10K Fixed Resistor 1/4W

10K Fixed Resistor 1/4W

A 10,000-ohm resistor rated for 0.25 watts

[10k-fixed-resistor-1/4w]
1M variable Resistor

1M Variable Resistor

An adjustable resistor with a maximum resistance of 1 Megaohm (1MΩ), used to control current, voltage, or signal levels in electronic circuits.

[1m-variable-resistor]
3V Buzzer Kit

3V Buzzer Kit

A low-voltage sound-producing module that operates on 3V DC supply. It is commonly used in DIY electronics, alarms, toys & indicators.

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single transistor mosquito

Build a simple mosquito repeller using a single BC547C transistor. Generates high-frequency sound to repel mosquitoes, perfect for DIY electronics projects.

single transistor mosquito circuit:

The mosquito repeller is a single-transistor mosquito repeller with BC547C that produces high-frequency sound to repel mosquitoes. The BC547C is used as an oscillator with a frequency of ultrasonic waves to scare the mosquitoes safely.

high-frequency mosquito sound:

Single Transistor Mosquito Repeller with BC547C is a really easy and efficient DIY electronics project that would repel mosquitoes with high-frequency sound. The BC547C transistor is used as an oscillator to produce ultrasonic frequencies, which are uncomfortable to mosquitoes but an inhuman sound. This project will suit hobbyists, students, and beginners in electronics. The circuit runs on a low-voltage DC power supply, thereby being safe to be used in the home. The ultrasonic sound is emitted by a piezo buzzer or a small speaker. The frequency of oscillation is the value of the components, i.e., the resistors and capacitors, which gives the possibility to tune to the best. The design is focused on being simple, stable, and cost-effective, and, therefore, is a good choice in educational electronics experiments or a homemade mosquito repellent.

⚡ Work & Installation (Input → Output):

  • Power Supply → 3–9V DC low-voltage supply.
  • BC547C Transistor → Acts as an oscillator generating high-frequency signal.
  • Frequency Components → Resistors and capacitors set ultrasonic frequency.
  • Output Device → Piezo buzzer or small speaker emits high-frequency sound.
  • Installation → Assemble components on breadboard or PCB, connect power and speaker, and test for ultrasonic output. Place the repeller in mosquito-prone areas.

Testing & Final Adjustments:

When it is assembled, turn the circuit on and ensure that the buzzer generates high-frequency sound. Change resistors or capacitors to make an optimal frequency selection to keep the mosquito repelled. Make sure that the BC547C transistor is in the correct orientation. The circuit should be tested in a safe place where pets are not present because some animals are sensitive to ultrasonic sound. Ensure that it has not overheated and that it is still operating. Use PCB or enclosure components with a securing material to ensure that they do not get damaged by moisture. The right testing will guarantee the effective and safe working of the mosquito repellents and is a good DIY project in the small indoor areas.

Frequently Asked Questions - single transistor mosquito:

What is BC547C?

A general-purpose NPN transistor used as an oscillator in this circuit.

Voltage required?

Typically 3–9V DC low-voltage supply.

Output type?

High-frequency sound emitted via a piezo buzzer or speaker.

Is it safe for humans?

Yes, the ultrasonic frequency is inaudible and safe for humans.

Applications?

Indoor mosquito repellent, educational electronics project.

Can frequency be adjusted?

Yes, by changing resistor and capacitor values.

Beginner-friendly?

Yes, simple components and low-voltage operation.

Continuous operation safe?

Yes, with proper heat management.

Can it affect pets?

Some pets may hear ultrasonic sound, so test carefully.

PCB needed?

Optional, breadboard works for prototype or learning purpose.

Md Jony Islam

Md Jony Islam

CalculatorToolsProject

Founder of Earthbondhon.com

a free online tools website designed to make everyday and engineering-related calculations easier for students, professionals, and hobbyists. The site offers a wide range of basic calculators across key categories, including Electrical Calculators, Electronic Calculators, and Time & Date Calculators.