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Simple Thunder Lightning Detector Circuit

Last updated on 28 May 2025 by Admin-Lavi Leave a Comment

This circuit explains how to construct a lightning detector a tool which is used by storm chasers!

A special kind of energy is created in the sky by lightning.

When a storm occurs this circuit detects the electricity and alert users by lighting up or emitting a sound.

As a result one can get more time to enter the safe place before the rain begins.

Circuit Working:

Simple Thunder Lightning Detector Circuit Diagram

Parts List:

CategoryItemQuantity
Resistors (All resistors are 1/4 watt unless specified)
10M1
330k1
100k1
15k1
33k1
Preset 10k1
Capacitors
Ceramic 100pF1
Ceramic 470pF1
Ceramic 10nF1
Ceramic 4.7nF1
Electrolytic 47μF2
Semiconductors
Transistor BC5473
Diode 1N41481
LED 20mA 5mm1
Piezo Buzzer1
Antenna 150mm (6 inch wire)1

When the circuit detects a discharge it is designed to flash an LED or sound an audible alarm tone via a piezo buzzer.

This allows users to take the right steps by providing them with early warning about coming storms.

Using the bias resistor values shown in the circuit diagram the lightning detectors capacity will be adjusted to the self oscillation to get the most relaxation which is one of its primary features.

The DC coupled oscillator sends feedback to the base of TR2 through the collector of transistor TR1.

The multiturn preset VR1 is used to control the overall loop gain.

While keeping an eye on test point TP1 transistor select preset VR1 for oscillation with a target of around 7V peak to peak in order to establish the lightning sensor.

+6V DC shall be seen at test point TP2.

To stop oscillation fine tune VR1 and gently connect with the aerial side of C1 with a screwdriver.

After one or two seconds the alarm will go OFF.

Make little changes and verify whether it continues.

Another option is to charge a plastic ruler electrostatically and bring it near the discharge which is around two meters from the aerial.

In standby mode the circuit uses around 600µA and is powered by a 9V battery.

With constant electricity it can monitor constantly for a whole year.

The current rises to 4 mA when the alarm is activated based on the low current sounder WD1.

For the best results a device that produces an immediate ‘pinging’ warning for any electrostatic pulse activity should have a minimum voltage of 3V.

Formulas:

To ensure that the circuit functions correctly and that the component values for a thunder lightning detector circuit are accurate one can use several kinds of formulas.

The main formulas and their uses are as follows:

The Base Resistor Calculation Process:

For a transistor to operate properly the base resistor (RB) is necessary.

It guarantees that the transistor operates in the active area and has the correct bias.

RB ​=​ VCC​−VBE​​ / IB

where,

  • VCC is the supply voltage of 9V
  • Base Emitter voltage of the transistor which is usually 0.7V for BC547 is represented as VBE.
  • Base current is IB.

To determine IB​:

IB​ = ​IC​​ / hFE

where,

  • IC is desired collector current
  • hFE is transistors current gain hFE for BC547 which is generally 100.

Timing and filtering capacitors and resistors:

For a simple resistor capacitor RC filter the cutoff frequency fc is calculated as follows:

fc ​= 1​ / 2πRC

where,

  • Cutoff frequency Hz is equal to fc.
  • Resistance Ω represents R
  • C equals capacitance F.

Dissipation of Resistor Power:

To ensure that resistors can keep up the power without overheating calculate the power dissipation:

P = I2 × R

where,

  • P is for power loss W
  • I is the resistors current through value A.
  • Resistance value Ω R

Capacitor Reactance:

To find out how capacitors XC affect the circuit calculate their reactance:

XC​ = 1​ / 2πfC

where,

  • C is the capacitive reactance Ω in XC
  • f is the signals frequency in Hz
  • C equals capacitance F

Power for the LEDs and buzzer:

To avoid damage be sure the current passing through the LEDs is right:

I = ​Vsupply − VLED ​​/ RLED

where,

  • I is the current intake A of the LEDs.
  • Voltage supply Vsupply stands for voltage.
  • VLED The forward voltage of LEDs is usually 2V.
  • The series resistor Ω in series is called an RLED.

These formulas might help to build and fix a thunder lightning detector circuit easily.

Adjust component values as necessary to meet design and testing requirements.

How to Build:

To build a Simple Thunder Lightning Detector Circuit following steps are required for connection of the circuit

Gather the parts:

  • Be sure each of the above mentioned circuit components are ready.

Make the circuit board:

  • On a circuit board arrange the parts as shown in the above circuit schematic.
  • Use wires to join the parts then solder them into position.

Install the TR1 and TR2 transistors:

  • Be sure the transistors are positioned correctly by placing them in the right spots on the circuit board.
  • Connect the TR1 collector to the TR2 base.

Connect VR1 Preset:

  • As shown in the circuit diagram connect the multiturn preset VR1 to the circuit.

Add Capacitor C1:

  • Connect the capacitor C1 to the circuit.
  • Connect capacitor C1 one end to the base of transistor T1 and other end between antenna and resistor R1

Add the Sounder WD1:

  • Connect the low current sounder WD1 to the circuit.
  • Ensure that it is connected correctly to provide the desired alarm function.

Connect Antenna:

  • The short wire should be connected to the circuit boards provided antenna spot.

Connection of Power:

  • Connect a 9V battery to the circuits battery connection to supply power.

Testing:

  • While keeping an eye on test points TP1 and TP2 transistors adjust preset VR1 for oscillation to meet with the given voltage standards.
  • Test the circuit by touching the aerial side of C1 or by following the electrostatic method given and fine tune to stop oscillation.

Last Minute Modifications:

  • Adjust the circuit as needed to make sure it works as planned.

Take note:

  • Always take care when soldering and working with electrical components.
  • Seek help from an experienced person if anyone is new to electronics or soldering and always verify every step to avoid mistakes or component damage.

Conclusion:

The Simple Thunder Lightning Detector Circuit may not be able to detect every lightning strike but it can give warnings of approaching thunderstorms.

A lightning detectors sensitivity, the size of the antenna and the outside environment these all influence show how effectively the circuit will work.

References:

Lightning detection

Prototyping a RF signal-based lightning warning device using with Internet of Things (IOT) integration

Filed Under: Sensors and Detectors

About Admin-Lavi

Lavi is a B.Tech electronics engineer with a passion for designing new electronic circuits. Do you have questions regarding the circuit diagrams presented on this blog? Feel free to comment and solve your queries with quick replies

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