Before using the headphone socket, the problem of determining the power supply voltage must be solved. At this time, the method of measuring the voltage will certainly be used. It will cause trouble to many friends who will not. Then the way of measuring the voltage of the headphone socket is introduced below.
First of all, it is necessary to confirm whether the voltage of each chip power pin is normal. Secondly, it is necessary to check whether the reference voltage is normal, and whether the working voltage of each point is normal. For example, when a silicon triode is turned on, the BE junction voltage is about 0.7V, while the CE junction voltage is about 0.3V or less. If the BE junction voltage of a transistor is greater than 0.7V (except for special transistors, such as Darlington transistors), it may be BE junction open-circuit signal injection method. The signal source is added to the input terminal, and then the waveform of each point is measured back to see if it is normal to find the fault point.
Sometimes we also use simpler methods, such as holding a tweezers in our hands, to touch the input terminals at all levels to see if the output terminals react, which is often used in audio, video and other amplifier circuits.
It must be that the thicker the conductor, the stronger the current it can withstand. But the current density is not the same. No matter how thick or thin the conductor is, the current density it can withstand varies little.
Current intensity is only independent of the cross-sectional area of the conductor. For example, the current of 10 amperes is 10 amperes, no matter how thick the current passes through the conductor, its current intensity is 10 amperes.
For example, a conductor with a square millimeter area has 10 amperes of current and a conductor with a square millimeter area has 10 amperes of current. Their current intensities are the same. They are all 10 amperes, but the current density is different. Of course, the current density in a conductor with a square millimeter is large. In this way, once the current transformer has problems, the circuit breaker and the arrester can not remove the fault, the upper circuit breaker trips to remove the fault, thus expanding the blackout scope, but also because of delayed removal fault, the current transformer will be burned.
Above is the detailed introduction of the power supply voltage measurement of the headphone socket. Please do these requirements when you use them correctly to ensure the normal use of the headphone socket.
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