Mobile Phone Circuit Diagrams

# Mobile Jammer Circuit

In the earlier post, we have studied about Simple FM Radio Jammer Circuit and its applications. Now, let us learn about one more interesting concept i.e. Cell Phone or Mobile Jammer Circuit.

Outline

• Introduction
• Circuit 1: Mobile Jammer Circuit using 555
• Components Required
• Operation
• Circuit 2: Simple Mobile Jammer Circuit Diagram
• Cell Phone Jammer Circuit Explanation

## Introduction

A Mobile Jammer Circuit, also known as a Cell Phone Jammer Circuit, is a device or equipment that may block mobile phones from receiving signals. A Mobile Jammer Circuit is essentially an RF transmitter that transmits radio signals in the same (or comparable) frequency band as GSM communication.

WARNING: In most countries, blocking or jamming radio signals is unlawful. Before utilising such gadgets, make sure you know the rules in your area.

In this project, I created two Mobile Jammer Circuits, one of which uses a 555 Timer IC and the other of which uses active and passive components.

## Circuit 1: Mobile Jammer Circuit using 555

#### Components Required

• 555 Timer IC
• Resistors – 220Ω x 2, 5.6KΩ, 6.8KΩ, 10KΩ, 82KΩ
• Capacitors – 2pF, 3.3pF, 4.7pF, 47pF, 0.1µF, 4.7µF, 47µF
• 30pF Trimmer Capacitor
• LED
• Coils 3 Turn 24 AWG, 4 Turn 24 AWG
• Antenna 15 Turn 24 AWG
• BF495 Transistor
• ON / OFF Switch
• 9V Battery

## Operation

I placed a cell phone near the circuit after creating it on a perf board and provided power to it (I am yet to turn on the switch). My phone was able to capture the majority of the signals before turning on the power because it was showing full bars.

The phone’s signal bars began to fade when I turned on the circuit, eventually down to a single bar.

As a result, I may conclude that this circuit inhibits signals but does not fully jam them.

## Cell Phone Jammer Circuit Explanation

If you understand the above circuit, this circuit analysis is simple and easy. For any jammer circuit, remember that there are three main important circuits. When they are combined together, the output of that circuit will work as a jammer. The three circuits are

• RF amplifier.
• Voltage controlled oscillator.
• Tuning circuit.

The RF amplifier circuit is made up of transistor Q1, capacitors C4 and C5, and resistor R1. The signal generated by the tuned circuit will be amplified as a result of this. The antenna receives the amplification signal via the C6 capacitor. Capacitor C6 will filter out the DC signal, leaving only the AC signal to be broadcast through the air.

The tuned circuit at the collector is turned on when the transistor Q1 is switched on. Capacitor C1 and inductor L1 make up the tuned circuit. This tuned circuit will function as a zero-resistance oscillator.

This tuned circuit or oscillator will create a very high frequency with minimal dampening. Both the inductor and the capacitor in a tuned circuit will oscillate at the same time.

The operation of the tuned circuit is quite basic and straightforward. When the circuit is turned on, the capacitor stores the voltage according to its capacity. A capacitor’s primary function is to store electrical energy. When the capacitor is fully charged, the charge will flow through the inductor. An inductor is a device that stores magnetic energy. When current flows through the inductor, it stores magnetic energy via the voltage across the capacitor, which gradually decreases until the inductor has stored all of the magnetic energy and the charge or voltage across the capacitor is zero.

The magnetic charge in the inductor decreases, and the current charges the capacitor in the opposite or reverse polarity. After a certain amount of time, the capacitor will be fully charged, and the magnetic energy across the inductor will be zero. The capacitor will charge the inductor once more before becoming zero. After a period of time, the inductor will discharge its charge and the capacitor will become zero, causing them to oscillate and generate the frequency.

The oscillations will be stopped if this circle runs up to the internal resistance. The RF amplifier feed is delivered to the collector terminal before C6 for gain or as a boost signal to the tuned circuit signal through the capacitor C5. The noise for the frequency generated by the tuned circuit is generated by the capacitors C2 and C3. The electrical pulses will be generated at random by capacitors C2 and C3 (technically called noise).

The RF amplifier’s feedback or boost, the tuned circuit’s frequency, and the noise signal generated by the capacitors C2 and C3 will all be combined, amplified, and broadcast to the air.

A cell phone operates at a frequency of 450 MHz. To block this 450MHz frequency, we’ll need to generate a 450MHz frequency with some noise, which will work as a basic blocking signal because the mobile phone receiver won’t know which signal it’s receiving. This allows us to prevent cell phone signals from reaching the phones.

So we generated the 450 MHz frequency in the above circuit to block the actual cell phone signal. The above circuit will operate as a jammer to block the actual signal in this case.

### Note:

• This circuit will work in the range of 100 meters i.e. it can block the signals of cell phones with in 100 meters radius.
• Usage of this type of circuits is banned in most of the countries. Usage of this circuit is illegal and if you caught by using this circuit, you can be imprisoned and also should pay large amount in the form of fine.
• This circuit can be used in TV transmission and also for remote controlled toys or play things.
• If the circuit is not working, just increase the resistor and capacitors values in the circuit. Increase the frequency of tuned circuit by using this formula F= 1/ (2*pi*sqrt (L*C)). Increase the inductor capacitor circuit components value for increasing the frequency.
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