3.5 To 10Mhz Simple Superheterodyne Receiver
The circuit operates primarily as a radio frequency (RF) signal processing unit, converting incoming RF signals into audio output. The frequency converter U1 takes an RF input and down-converts it to a 455 kHz IF signal, which is then processed by U2, the variable attenuator. The gain control resistor R9 allows for fine-tuning the output level of the IF stage, ensuring optimal performance based on varying signal strengths.
The NE602 mixers (U1 and U3) are integral to the conversion process, providing high selectivity and low distortion, essential for maintaining signal integrity. The audio output stage, using the LM380N-8, amplifies the processed audio signal for output. The use of microminiature transformers (T1, T2, T3, and T4) minimizes space while allowing for efficient signal coupling between stages.
Capacitors C10 and C11 play a critical role in filtering and stabilizing the circuit. The specified range of capacitance values is crucial to prevent distortion, particularly in audio applications. A printed stripboard is utilized for assembly, providing a compact and efficient layout for the components, while the plastic stick-on feet and 4-40 hardware ensure a secure and stable installation.
Overall, this circuit is designed for effective signal processing in radio frequency applications, balancing size, performance, and ease of assembly. In this circuit, Ul is a frequency converter that feeds the 455-kHz IF stage U2 and detector U3. U4 is the audio output stage. R9 is a gain control that varies the gain of U2. Coil data is given in the part list. R6, R710k, YiWcarbon composition R910kpotentiometer T1, T210.7 MHzmicrominiature (7mm)Mouser PN 42IF223 IF transformer, green core T3,T4455 kHzmicrominiature (7mm)Mouser PN 42IF203 IF transformer, black core U1, U3NE602double-balanced mixer U2MC3340variable attenuator U4LM380N-8audio amplifier U578L05100 mA miniature+5V regulator * C10 and C11 can range from 0.1 to 0.22. Valves greater than 0.33 cause distortion. Other: Printed stripboard, DSE PN H5614 or equivalent, cabinet, plastic stick-on feet, 4-40 hardware, etc.
🔗 External reference
Related Circuits
This prescaler is designed to divide an input frequency by 1000. It can handle a maximum input frequency of 3.5 GHz and converts it into 3.5 MHz, which can be measured using a standard frequency meter. The prescaler circuit consists...
The amplifiers of an LM3900N device can be utilized to create an audio mixer unit that allows for the combination of three separate audio signals into a single composite output. The audio mixer circuit provided operates with a single...
This schematic represents a tone transmitter. When using sufficiently small resistor values, it generates a tone. A resistive microphone (such as a carbon microphone) can be placed in parallel with or replace the resistor, allowing modulation of the tone...
This sunlight-controlled lamp utilizes a light-dependent resistor (LDR) as the sunlight sensor and comprises a total of 25 high-brightness white LEDs. Each row of LEDs is connected in series with separate resistors. The operation of the circuit is straightforward....
Construct a basic audio amplifier utilizing transistors. While integrated circuit (IC) designs are available for this purpose, the intention is to use transistors to gain practical knowledge about their amplification capabilities. The article "Amplifier Basics - How Amps Work...
The circuit diagram provided illustrates a straightforward setup. There is no requirement for complex circuitry; simply connect a 0-1 V full-scale deflection (FSD) moving coil meter across the designated pins of the integrated circuit (IC). Adjust the potentiometer as...