9014 Chip Pin Diagram Circuit Diagram

Circuit principle: the indicator is connected in parallel on the telephone line and supplies power to the circuit after changing the polarity of D1 D4. When the telephone line is not used, the telephone line voltage is distributed at 48V. The 48V voltage is added to the resistors R3 and R4. The partial voltage obtained by R4 is greater than 0.7V, and the triode T2 is fully turned on. When T2 is turned on, the triode T1 loses the bias voltage, T1 is cut off, and the LED does not emit light. Clarify the ability to use telephone calls at the moment. When someone is using the telephone, the telephone line voltage drops to 9V distribution. At this moment, the short voltage on R4 turns on T2. T1 passes through the resistance R2 or the bias voltage, T1 turns on, and the LED lights up, indicating that someone is using the telephone. Please do not use it for the time being.

Precautions for component selection and manufacturing: all component types shall be selected according to the above circuit diagram, and the triode shall be selected 9014, which shall be doubled

If the number is greater than 150, the pins of the triode are shown in the figure below: