Figure 3 is a practical 50m FM wireless headset transmitter part of the circuit. The circuit is divided into oscillation and signal amplification. L1, C2-C5, V1 and other components are similar to the improved capacitor three-point oscillator of the black-and-white TV high-frequency head local oscillator circuit. It has good frequency stability and does not run for a long time. Practice has proved that this improvement is adopted in amateur situations Type capacitor three-point oscillator is fully competent. The author directly soldered the collector of V1 with an electric soldering iron for a few seconds. Under the condition that the temperature of the triode is very high, the normal radio reception is still normal, and there is no frequency running phenomenon. The frequency of the oscillator is mainly determined by L1 and C2. By fine-tuning L1, the range of 88-108MHZ can be covered. The audio signal is coupled to the base of V1 via R6 and C11, and the capacitance between the e and b poles of V1 changes the oscillation frequency with the change of the audio voltage to achieve frequency modulation. In this circuit, L, ~ L3 are wound flat with a single layer of 0.31mm enameled wire on the middle 3.5mm round bar. After adjusting L1 inter-turn spacing to fine-tune the oscillation frequency, and then fine-tuning the inter-turn spacing between L2 and L3 to oscillate the harmonic oscillator frequency, the maximum output power is obtained.
The driving recorder with a screen allows the driver to directly see the recording of the recorder,
and can also perform related operations through the screen. At the same time, Hikvision`s Dash Cam with a screen The recorder
can not only be operated directly through the screen, but also can be used for real-time video viewing, historical video playback
and other operations through the mobile APP "HIK DASH CAM".dash cam with touch screen,touch screem with dash cam,large screen dash cam,large screen dash cam
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