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Cut Phone Line Detector

This cut phone line detector circuit is used to detect whether your phone line is active or not. Components List: R1,R2,R3 = 22M Ohms R4 = 2.2M Ohms C1 = 0.47uF/250V Mylar caps D1 = 1N914, NTE519, or other small signal diode Q1 = 2N3904, NTE123AP Q2 = 2N3906, NTE159 Q3 = IRF510, NTE2382,  MosFet

4 Transistor FM Tracking Transmitter

The following diagram is the FM tracking transmitter based on 4 transistors. No additional notes for this tracking transmitter diagram, try to discover this circuit by yourself.. 🙂 Components list: R1 = 100K Ohms R2 = 10 Ohms R3 = 47K Ohms R4 = 220 Ohms C1 = 4.7uF/16V C2, C5 = 1nF C3 =… Read More »