MAGAZINE OF STUDENT RESEARCH Mosquito Killing Machine Saif Ali Abd Almonem., Ameer Khudhur Abd AlBaqi., Athraa Abd Alhussein Department of Electronic and Communications Engineering, Faculty of Engineering, University of Kufa, Iraq. ABSTRACT: This work is aimed at reducing the number of mosquitoes through the use of electronics. The work entails the design and construction of a high voltage tripler circuit for a mosquito Zapper which can electrocute mosquitoes. This circuit is not complicated and does not have many components .It can easily attract the flies and when the flies approach between the two plates, they get shocked and killed. Keywords: Mosquito; High voltage; Power transistor; Voltage Regulator. 1. INTRODUCTION A mosquito zapper is a device used for killing mosquitoes using high voltages. The mosquito zappers are in different shapes and sizes but consist of the same basic building blocks namely: 12345- High voltage generating circuit A mesh assembly or metal plates Power supply or charging battery Control device High voltage mini transformer The high voltage circuit generates voltages in the range of 700 - 1000 volts to a mesh assembly which traps the insects. © 2019 Electronic and Communications Department, Faculty of Engineering, University of Kufa, Iraq. All rights reserved. 2 Magazine of Student Research (MOSR) 2. MATERIALS AND METHODS 2.1 General Circuit Diagram and Its Operation Principle The main body resistance of most bugs and mosquitoes fall within the range of 0.70 – 0.75 Ω and the required Zapper voltage is from 600 to 1200 volts ac. Figure 1.1 is the voltage doubler circuit diagram of the Zapper. Our general circuit has two parts, the first part is converting dc to ac by using mini high transformer. When the DC voltage converted into AC voltage the next is to make this voltage as higher as possible by using the idea of Voltage Multiplier or Tripler and Quadrupler, if we have 5V AC we can make it 1KV DC by using this Concept. The circuit can convert AC Voltage from a low rate to a high rate using diodes and capacitors, it can provide any voltage range you want by duplicate it. Figure 1.1 Typical circuit of the Voltage Multiplier circuit. This circuit works like this, At the negative cycle of the input signal, the diode D1 is forward biased and acts like a short circuit or just a wire while the diode D2 is reverse biased and acts like an open circuit, so the capacitor C1 will charged up to -VP (Peak Voltage) of the total input voltage. At positive cycle of the input signal, the diode D1 is reverse biased and acts like open circuit so capacitors C1 is still have the voltage(-VP) charged in it, and C2 will charge by the peak (+VP) of the input voltage whereas diode D2 acts like a short circuit ,see Equations for more details. The output is rectified as shown in Figure 1.2. Figure 1.2 shows the input signal, a sinusoidal wave and an output after rectified . © 2019 Electronics and Communication Department, Faculty of Engineering, University of Kufa, Iraq. All rights reserved. Magazine of Student Research (MOSR) 3 2.2 Mini Inverter circuit Now this circuit its works as an oscillator that turns off / turns on the dc voltage rapidly the transistor produces a waveform like a square wave which the ferrite transformer can see it like an AC voltage, When power is applied to the circuit, the transistor and the center tapped transformer instantly start oscillating at the specified high frequency. This forces the battery current to pass across the FT1 winding in a push pull manner. We have used a power transistor that has high dc gain and high switching operation. Any power transistor can works in this circuit we have tried many power transistors. Figure 1.3 Mini Inverter circuit. Now the output of this circuit can be so useful for our voltage multiplier circuit, the output of transformer is around 600V-750V. And frequency is 100 KHz - 200 KHz. The winding inside the coil of transformer is calculated for working with 3-5V DC supply, The above switching generates a proportional induced high voltage across the secondary winding of FT1. 2.3 Components Our components its in general combination of capacitors and diodes, in addition we have the transformer and the transistor, also the voltage regulator which can provide the transistor no more the 5v dc. Figure 1.4 Ferrite Transformer. Figure 1.5 Polyester Capacitor. © 2019 Electronics and Communication Department, Faculty of Engineering, University of Kufa, Iraq. All rights reserved. 4 Figure 1.6 Ferrite Transformer. Magazine of Student Research (MOSR) Figure 1.7 Power Transistor. Figure 1.8 Voltage Rregulator. 2.4 Printed Circuit Board We unfamiliar with PCB and how they build, but after searching for a little days we get such huge information on how to build PCB. First of all, the pcb is an easier way to prototype any project, it has a less effort in connections than the commercial breadboards. We designed our project using Proteus, and we have got the following PCB layout. Figure 1.9 PCB Layout. Figure 1.10 PCB Visualizer. © 2019 Electronics and Communication Department, Faculty of Engineering, University of Kufa, Iraq. All rights reserved. Magazine of Student Research (MOSR) 5 Figure 1.11 The Resulted PCB 3. Equations This the equations for the Voltage Doubler circuit that shown in the figure 1.1. by Kirchhoff’s voltage law if we take an outer loop we will have this equation: −𝑣𝑝 + 𝑐1 + 𝑐2 = 0 Where C1 = - VP −𝑣𝑝 − 𝑣𝑝 + 𝑐2 = 0 𝑐2 = 2𝑣𝑝 4. Conclusion We have many conclusions but in summary for this project we have the following: 1- Easy to build. 2- Easy to understand. 3- A useful project used to reduce the amount of fillies. Acknowledgements This work was supported by the Electronic and Communications Department, Faculty of Engineering, University of Kufa, Iraq. Thanks to A.L Salam Al-abassi for supporting me in this project and providing us all components we need. References  Robert Boylestad., Louis Nashelsky. Electronic Devices and circuit theory 11th. 105-115. © 2019 Electronics and Communication Department, Faculty of Engineering, University of Kufa, Iraq. All rights reserved.