Method of realizing home TV station based on 7805

Using the 78/79 series three-terminal voltage stabilizing IC to form a voltage-stabilizing power supply requires very few peripheral components. There are also protection circuits for overcurrent, overheating and adjustment tubes inside the circuit. It is reliable, convenient and cheap to use. The number after 78 or 79 in the model number of this series of integrated voltage stabilizing ICs represents the output voltage of the three-terminal integrated voltage stabilizing circuit.
7805 is a regulated power supply circuit that outputs positive 5V DC voltage. The IC uses an integrated voltage regulator 7805, C1 and C2 are the input and output filter capacitors respectively, and RL is the load resistor. When the output current is large, the 7805 should be equipped with a heat sink.
Many families now have household appliances such as televisions, VCDs, video recorders, game consoles, and even video cameras and DVDs. What is introduced below is this kind of TV signal repeater, which has the characteristics of simple circuit, low cost, and easy production.
The working principle
circuit is shown in the figure below: The working principle of this circuit is that the radio frequency signal is sent to the high-pass filter composed of C1, L1 and C2 through the 75 ohm radio frequency cable, and the frequency lower than 45MHZ is filtered out, and then passed through the triode The preamplifier composed of 9018 and others is amplified and sent to upc1651 by capacitor C3 for power amplification, and its output signal is emitted through a whip antenna of about 60cm. 7805 and other components form a voltage regulator and power indicator to provide 5V power supply for upc1615.