Simple Ham Radio Circuit Audio Filter Using 741 IC

Here’s a design circuit that has function that it will help to filter out the interference signal and ensure that the signal received from the Morse code station stand out. This is the figure of the circuit;

The earliest mode of radio communications is the use of Morse Code on a continuous wave carrier(CW) which is interrupted to generate a dit and dah in forming an alphabet. Component: 741 IC, Resistor, Capacitor, Battery, Inductor, Switch.[Circuit diagram source: electronics-project-design.co]

FM Radio Using TDA7000

Here’s a design simple circuit using TDA7000 that can build an FM radio with a minimum of components; most of them so easy to manage, like the ceramic capacitors that do not require polarization and only two resistors. Here’s the figure of the circuit;

The components you will employ will be of small dimensions and low cost. Even the integrated circuit itself, the TDA 7000, is not of great cost.

Simple AM Radio Circuit Using Transistor

This is a one design for simple circuit of AM transmitter, where the AM transmitter using ceramic resonator / filter of 3.587 MHz is presented here. This circuit is based on the core to the operation of the transistor circuits. This circuit is based on transistor for operation the circuit. This is the figure of the circuit.


Resonators / filters such as the frequency of 5.5 MHz, 7 MHz and 10.7 MHz may also be used. Using a different frequency filters / resonators will involve corresponding variation in the value of inductor used in the oscillator tank circuit is connected to the collector of transistor T1. AF input for modulation is inserted in series with the emitter of transistor T1 (and resistor R4) using a transistor radio type audio transformer such as a driver on the circuit. Based on the figure, the modulated RF output is developed across the tank circuit which can be tuned to the resonance frequency of the filter / resonator with the help of gang condenser C7. Next two stages formed with low-noise RF transistors BF495 is, in fact, connected in parallel for amplification of modulated signal coupled from collector of transistor T1 to the base of the transistors T2 and T3. Combined output from the collector of T2 and T3 is to the antenna feed through 100pF capacitor C4. Circuits that can be easily collected in the general purpose PCB. Range from transmitter is expected to be one to two kilometers. Circuits that require regulated 9 volt power supply for operation.

Simple Single Transistor Radio

This is a design simple circuit diagram of radio. This circuit radio is uses single transistor and few other passive components. In this circuit transistor that using is BC547. This is the figure of the circuit.


The operation and principle work of this circuit is when C6 and L1 forms a tank circuit which picks up the signal from your desired radio station. Diode D1, capacitor C2 and resistor R1 does the detection of the picked signal. The detected signal is coupled to the base of Q1 through capacitor C3.The Q1 gives required amplification to the signal. The resistor R2 is used to bias Q1.R3 limits the collector current of Q1.The audio output will be available at the collector of Q1 and it can be heard by using a high impedance head phone. This radio will work only at places where there is reasonable radio signal strength.

The circuit can be powered by a 3V battery. The antenna for this circuit can be use a 1 M long wire. The headphone must be a high impedance (2 to 3K) type. If diode AA121 is not available you can use AA112, AA116 or 1N34. The inductor L1 must be a 0.35mH, center tapped one. The radio can be tuned by adjusting the variable capacitor C6.