Circuit Diagram Of A Mosquito Swatter / Mosquito Racket

Simple circuit diagram to know how mosquito swatter works?

How mosquito swatter works ?

This is a simple diagram which showing how mosquito swatter/ Mosquito racket works ?
For descriptive circuit diagram of mosquito racket check bellow.

Mosquito swatters step up transformer

Mosquito rackets Transformer

S1-F2 - Primary have 3t 0.4mm ENCU
S2-F2 Primary have 3t 0.4mm ENCU
S3-F3 Secondary have 360t 0.25mm ENCU

Actually this is a step up transformer which is supplying a high voltage .It's converting voltage dc to ac.

Descriptive Circuit diagram of a mosquito killer or mosquito swatter

Circuit diagram of a mosquito racket bat

A rechargeable mosquito killer racket (also known as an electronic mosquito swatter) looks like a lightweight tennis or badminton racket, but internally it is a powerful high-voltage electronic circuit. It is widely used to kill mosquitoes and small insects instantly through an electric shock discharge.

Many technicians, electronics students, and DIY hobbyists often ask for a clear circuit schematic and transformer winding details to repair damaged mosquito bats. In this detailed guide, we will analyze the complete circuit schematic, how the high-voltage step-up transformer works, the voltage multiplier stage, and troubleshooting tips for common faults.

How an Electronic Mosquito Racket Works

The working principle of a mosquito swatter is divided into four fundamental electronic stages:

1. DC Power Source (Battery):
   
   
   Most standard mosquito rackets use a 3.7V lithium-ion battery or a 4V lead-acid rechargeable battery. When the safety push switch is pressed, DC voltage flows into the primary oscillation stage.
   
   
2. Inverter / High-Frequency Oscillator Stage:
   
   
   A high-speed switching transistor (commonly D882 or 2SD882 NPN transistor) is combined with a feedback winding on a small ferrite core transformer. This converts the low-voltage Direct Current (DC) into a high-frequency Alternating Current (AC).
   
   
3. Step-Up Transformer Stage:
   
   
   The high-frequency AC current enters the primary winding and induces an amplified high-voltage AC output (typically 200V to 300V AC) on the secondary coil.
   
   
4. Voltage Multiplier & Storage Stage (Cockcroft-Walton Circuit):
   
   
   The AC voltage from the secondary winding passes through a ladder network made of high-voltage fast-recovery diodes (such as 1N4007) and polyester film capacitors (typically 2KV rated). This stages multiplies the voltage up to 1500V – 2500V DC and stores the charge across a high-voltage output capacitor.
   
   

When a mosquito touches the outer metal mesh and the middle wire grid simultaneously, it bridges the gap, triggering an instantaneous electric spark discharge that eliminates the insect.

Mosquito Racket Step-Up Transformer Winding Specifications

If the internal transformer burns out or has an open coil, you can rewind it manually using the following exact winding specifications:

• Core Type: Small Ferrite EE or EI Core.
  
  
• Primary Winding 1 (S1 - F2): 3 Turns using 0.4mm (AWG 26) Enameled Copper Wire (ENCU).
  
  
• Primary Winding 2 (Feedback) (S2 - F2): 3 Turns using 0.4mm (AWG 26) Enameled Copper Wire (ENCU).
  
  
• Secondary High-Voltage Output (S3 - F3): 360 Turns using 0.25mm (AWG 30) Enameled Copper Wire (ENCU).
  
  

Technician Note: Ensure proper insulation paper (such as Kapton tape or polyester tape) between the primary and secondary layers to prevent high-voltage arcing inside the core.

Main Electronic Components List

To build or repair a mosquito bat circuit board, you will need the following core components:

• Transistor: D882 (2SD882) NPN Transistor with a small heatsink (if needed).
  
  
• Transformer: High-frequency step-up ferrite transformer (as per winding data above).
  
  
• High Voltage Diodes: 1N4007 or fast switching 1000V diodes (4 to 6 pcs).
  
  
• High Voltage Capacitors: 2KV / 3KV (222, 103, or 472 high-voltage ceramic/polyester disc capacitors).
  
  
• Storage Output Capacitor: 2000V (2KV) 15nF to 22nF film capacitor across the net.
  
  
• Resistors: 1K Ohm to 2.2K Ohm base drive resistor; 10M to 20M Ohm bleeder resistor across the output net (for user safety discharge).
  
  
• Switch & Battery: Micro push button (tactile or leaf switch) and 3.7V / 4V rechargeable battery.
  
  

Common Faults & Practical Repairing Solutions

If your mosquito racket stops sparking, check the following points in order:

• No Spark & LED Off:
  
  
  Check battery terminal voltage. If the battery voltage drops below 3.2V, replace or recharge the cell. Inspect the power push button for carbon corrosion.
  
  
• Red LED Lights Up, But No High Voltage Spark:
  
  
  In 80% of cases, the switching transistor D882 fails short or open. Desolder the transistor and test its base-collector-emitter junctions with a digital multimeter in diode test mode.
  
  
• Weak Spark / Very Low Shock:
  
  
  Inspect the high-voltage polyester output capacitor. If this capacitor leaks or loses capacitance, replace it with a fresh 2KV rating capacitor. Also check for short circuits caused by bent wires on the physical wire mesh.
  
  
• High Voltage Remains on Net After Release:
  
  
  The bleeder safety resistor (10M - 22M Ohm) across the metal grid has opened. Replace it immediately to prevent accidental shocks to the user.
  
  

Safety Warnings

This circuit generates lethal voltages for small insects, between 1500V and 2500V DC. While the current (amperage) is very low, touching the energized net or output capacitor can give an extremely painful shock. Always discharge the output capacitors using an insulated screwdriver before touching the PCB.

Save this technical wiring diagram for your workshop reference and share this guide with fellow electronics repair technicians!

This is a full circuit diagram of a mosquito racket bat. All capacitor diode transistor switch battery.
I think this is very helpful circuit diagram.
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