The integrated circuit signal tracker has simple circuit, only one low-power integrated power amplifier circuit LM386 and five capacitors can form a complete machine, and the tracking ability is very strong. From the tuning circuit to the power amplifier circuit, the fault can be easily detected. Due to the loud sound, the speaker can also be used to play when checking the medium amplifier and low amplifier circuits. There is no need to hang headphones, which is very convenient to use.

The circuit principle is shown in the figure above. CL is the DC isolation capacitance; C2 is the output capacitance; The function of C3 is to prevent self excitation; C4 is the power filter capacitor.

The signal is input from pin ③ of the integrated circuit LM386 through cl. because the input end of LM386 is micro current bias and has a wide frequency response, the detection can be completed without external diode. The signal is amplified and output by LM386 ⑤ pin. Pin ① and pin ⑧ of LM386 are gain control, and 10 is directly used μ The capacitance of F connects the two pins to obtain the highest gain.

The printed circuit board of the machine is shown in the figure below. Install all components in one 2cm & ties; On the 3.5cm printed circuit board, as long as the selected components are correct and the wiring is correct, it can work normally without debugging. The earphone socket needs to be reformed to act as a power switch. Since the signal tracker consumes little power and the static current is only about 4mA, it can be powered by four No. 5 batteries. If 6V laminated batteries are used, the volume can be further reduced.

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