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Bug Zapper Circuit – DIY Projects For Eliminating Insects

We are all aware of the irritation mosquitoes bring to our day-to-day lives. Thus, it is only natural if you want to get rid of them for good. Besides the common and sometimes overrated insecticides, have you ever thought about electrocution? Yes, it is a possible venture that requires a bug zapper circuit. 

A bug zapper attracts insects/bugs via an ultraviolet light emission. Then, the device electrocutes them between the two high-voltage wire grids. 

Today we will show you how to build the electronic circuitry of a mosquito swatter bat/bug zapper

Circuit Example of a Mosquito Swatter Bat

Our first basic concept involves using electrocuting equipment that is both fun and clean.  

Circuit Diagram

A basic circuit diagram of a mosquito swatter bat

A basic circuit diagram of a mosquito swatter bat

How the Circuit Functions

  • C1 and R1 plus the preset determine the oscillation frequency. 
  • Then, we have TR1 built from an EE type of ferrite core, forming a small ferrite core transformer. 
  • The circuit’s compatible with a 3V battery pack (DC supply) that you’ll construct by placing some AAA cells in series.
  • If you apply power to the circuit, the center-tapped transformer and transistor oscillate at the recommended high frequency. Consequently, the battery current passes crossway through the TR1 secondary output winding in a push-pull manner, generating high output voltage (about 200V) at the winding.
  • Additionally, you can use a Crockcroft-Walted ladder network at TR1 output to raise the voltage further (to about 600V). Afterward, the 2uF/1KV capacitor steps it up and stores the high voltage energy without discharge. The voltage then undergoes rectification and goes into the bridge rectifier for further rectification. 
bridge rectifiers operation

(bridge rectifiers operation)

  • Bringing the output terminals of the 2uF capacitor at closer distances makes the electric power in the capacitor break down the air barrier. It’ll then arc crossway the terminal gap as a flying spark.
  • Consequently, it’ll stop for a moment until the capacitor recharges enough to produce another spark.
  • Apply this circuit on a mosquito swatter but remember to;
  • Connect or tie the 2uF capacitor’s end terminals crossway the external and internal bat mesh layers.
  • Weave and tightly position the metal mesh layers over a solid plastic frame at distances apart from each other. It’ll prevent sparking. 
  • Finally, if a mosquito flies over, the swatter bridges it between the metal meshes, and the high voltage emission conduction follows. It instantly kills the insect with the spark. 

Making the Ferrite Core Transformer

Our mosquito zapper above also has a transformerless charger circuit. You can use it to charge the 3V rechargeable battery by connecting it to the main supply during insufficient power generation. 

Circuit Example of a Commercial Mosquito Zapper

Let’s now discuss the second commercially designed mosquito racket. 

Circuit Diagram

Circuit diagram of a mosquito zapper

Circuit diagram of a mosquito zapper

How the Circuit Functions

  • Pressing the power switch SA energizes the high-frequency oscillator with a step-up power transformer T and transistor VT1. Often, the power supply is from a 3V Direct current with a boost from T to about 500V. 
  • Then, the ladder network with capacitors C1-C3 and three 1N4007 diodes step up the high voltage 500V range to about 1500V. The high voltage PPC capacitor then stores the voltage. 
  • Next, the 1500V terminates in the mosquito racket net, whereby it can electrocute a closely nearby mosquito. 
  • Lastly, use LED to know the battery power life and to display the off/on circuit state. A tweakable series resistor R1 is ideal for improved battery life.  

Component selection

Some of the essential electronic components needed include;

  • PPC type capacitors (minimum of 630V),
  • Resistor (1/4W or 1/8 W),
  • Diodes (1N4007) or FR107/BA159,
  • LED (3mm tiny 20mA), or
  • 2N5609 oscillator transistor (alternatively use Bipolar transistors D880 or 2N2222). 

 Building the High Voltage Transformer

  • You will first need a 2E19 type ferrite core with a matching plastic bobbin.
  • L1 comprises a magnet wire with about 22 turns or an enameled copper wire of φ0.22mm. Contrarily, L2 has around eight turns of magnet wire but a similar φ0.22mm enameled copper wire. 
  • Lastly, we have L3 consisting of a secondary winding of round 1400 metal tuns and an enameled copper wire of φ0.08mm.  

Caution; Our circuit design above has no isolation from mains input voltage which means it’ll contain lethal mains AC voltage. Therefore, handle and test the circuit with extreme caution when powering it. 

How to Build a Portable Bug Zapper

Generally, designing a bug zapper depends on its design, size, and types of bugs targeted. 

Materials needed

  • Blacklight/ a UV LED light bulb, 
  • Handsaw,
  • Glue gun, 
  • Drill, 
  • Stapler wire,
  • Soldering gun,
  • Screws, 
  • Plywood,
  • A 1-yard squared 1/4” mesh wire/grid,
  • Six long wooden dowels
  • Two garden plant vase dishes,
  • A new 6V rechargeable sealed lead acid battery, and 
  • Circuitry from an old rechargeable lantern. 


  1. Make the bug zapper’s foundation.

First, build a round wooden base plate with a similar diameter to the inside of a plant vase cover. Then, tighten the wooden base plates with vase covers by drilling their sides.

Next, equally, drill about six holes in the wooden base plates. After, place the dowels in the holes to strengthen the frame and ensure insulation between the meshwork. 

Make a cylindrical shape out of the mesh while ensuring they don’t touch while they overlap each other. Use a spade bit to make a hole for light fitting at the plate’s center. 

  1. Fit the zapper LED bulb/blacklight; electrically fit the bulb and hot glue it.
UV purple blacklight

(UV purple blacklight)

  1. Electrify the mesh gride; First, solder in the red and black wires near the top surface of the mesh. Afterward, use the soldering gun to weld any overlapping metal mesh.
  2. Add the component of the bug zapper; Here, you can either wire or glue the circuit boards, battery, and lantern components into their stipulated areas on the bug zapper. 
  3. Take the carrying handle of the lantern and reuse it for the zapper. Later, drill a hole on the endcap before mounting the power cord, LEDs, switch and handle. 
  4. Finally, glue everything in place. 

a complete bug zapper

(a complete bug zapper)


We hope you’ll find the above guidelines easy to comprehend and follow in your electronic systems. For more information, you can reach out to us. We’ll be thrilled to help. 

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Emma Lu
Our professional engineering support saves our customers a lot of trouble and loss. >>>>>> After you place the order, our engineer will conduct technical reviews to make sure the parts can be mounted well/correctly on the boards. We will check if the component packages match well with the Gerber footprints, if the part numbers you provided match well with the descriptions, and if the polarity is clearly marked. >>>>> When your design is ready, please send your Gerber and BOM so we can quote and start!