Author Archive

AVC Automatic Volume Control

AVC - The featured circuit controls a volume line automatically. It delivers an output voltage of approximately 4 volts peak to peak. This voltage remains relatively constant by input voltages ranging from several hundred milivolts to serveral volts. This electronic circuit is not highly recommended for Hi-Fi applications because its noise factor is way above [...]


Field strength meter

This circuit measures the strength of a radiated signal from a transmitter. It is commonly used by model airplane builders to check whether their transmitter are really transmitting the radio signal. Using this FS meter, one can quickly determine whether the problem lies on the transmitter or the receiver module.
A single transistor T1 is the [...]


Frequency converter

This is a 35.3 to 10.7 MHz converter circuit. It converts the 35.3 MHz signal coming from a VHF/UHF tuner down to an FM tuner to decode the TV audio in FM quality. The IC being used (TBA120) is one of the most common components in radio and TV circuits. Although it was designed as [...]