The scenario
A technician needs a simple, battery-powered detector to verify the presence of an LNB signal while aligning a satellite dish. The circuit converts the RF envelope to DC, compares it to a threshold, and activates both a visual and audible alert.
What is in this drawing
Read the decisions behind it.
01
Used an AC source to represent the dish LNB signal and a diode envelope detector to convert RF level to DC
02
Added a transistor switch with a resistive divider to trigger LED and buzzer only when signal strength exceeds the threshold
Reusable for other RF signal presence detectors where a simple threshold-triggered audible and visual alert is needed, such as antenna alignment or cable continuity testing.
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