Transmitter - Received AM radio

This circuit utilizes a ceramic tuning resonator with a frequency of 3.587 MHz, alongside resonator filters available at frequencies of 5.5 MHz, 7.7 MHz, and 10.7 MHz. The transmission range of the device is approximately 2-4 km. The circuit operates on the principle that the filter resonator and ceramic filters raise the frequency of the resonator filter value. This frequency is amplified by a transistor, which can be designated as T1. Additionally, a capacitor (C7) is required as a regulator or for placement. Sound signals are superimposed over an audio transformer. The frequency generated by the resonator filters and T1 is fed to subsequent amplification stages to achieve the desired power output to the antenna. Transistors T2 and T3 function as buffers and serve as the final power amplifier. For AM radio applications, the ZN414 IC, which may be difficult to find, can be replaced with the equivalent MK484 IC. This IC covers frequencies from 550 kHz to 1600 MHz and includes a series of components such as a radio tuner, RF amplifiers, automatic gain control, and an AM detector. The voltage regulator or power transistor is implemented using a BC108B, with additional components including four 1N4148 diodes, resistors of 2.7 kΩ and 820 Ω, and a 10 kΩ trimpot, which is used to control selectivity across the entire circuit. A Class A and Class B amplifier configuration is employed to ensure that the modulated signal does not get lost.

This circuit design emphasizes the importance of the resonator filters in frequency selection and amplification, which are critical for effective transmission. The ceramic resonator's stability at 3.587 MHz provides a reliable frequency reference, while the additional frequencies available from the filters allow for versatility in applications. The amplification stages, particularly with the use of transistors T1, T2, and T3, are crucial for boosting the signal strength to the antenna, ensuring that the transmission can reach the intended distance of 2-4 km.

The integration of the MK484 IC streamlines the overall design by incorporating multiple functions necessary for AM radio operation, such as RF amplification and automatic gain control, which enhances the quality of the received signal. The use of a BC108B transistor as a voltage regulator ensures that the circuit operates efficiently and with minimal noise, while the carefully selected passive components, including diodes and resistors, contribute to the circuit's overall stability and performance.

The trimpot allows for fine-tuning of the circuit, enabling adjustments to be made for optimal selectivity, which is especially important in crowded frequency environments. The Class A and Class B amplifier configuration further enhances signal fidelity and power efficiency, making this circuit suitable for various AM broadcasting applications. Overall, this design showcases a well-rounded approach to creating a reliable AM transmitter capable of operating within the specified frequency range and achieving the desired transmission distance.Using ceramic tuning 3. 587 mhz resonator and resonator filters are also sold with a value of 5. 5mhz, 7. 7 mhz and 10. 7 mhz. Distance transmitter range is approximately 2-4km. the working principle of this circuit are filter resonator/ceramic filtersraise the frequency of the value of the resonator filter. This frequency is amplified by the transistor can be changed t1. Frequency so need C7 as a regulator / placement. sound signalsuperimposed over the audio transformer. frekuensi which awakened byresonator filters and t1 is fed to the next amplifystrengthened so as to achieve the desired power passed toantenna. t2 and t3 as a buffer as a final power amp. For AM radio because it`s hard to find IC ZN 414then now could be replaced with the equivalent of IC MK 484.

Frequency coverage between 550 kHz-1600 mhz, 3 pins of this IC includeseries of radio tuner, RF amplifiers, automatic gain control, the AM detector. The series voltage regulator or a power transistor made by BC108B, 4diada IN 4148, 2k7, 820R, and the 10K trimpot, trimpot functions forselectivity of the controller of all series.

Then weusing a booster class A and class B amplifier for signalmodulated not disappear. 🔗 External reference