Some hardware design experience summarized by the master (II)

6: DC feedback is to stabilize the static operating point, and AC feedback is to improve the performance of the amplifier.

7: The series-parallel relationship between capacitor and resistor is reversed. The inductance should be the same as the resistance, but there is also the concept of mutual inductance, so there is still a difference? Need to ask for a certificate.

8: Many of the oscilloscope's digital displays are displayed only when multiple cycles are displayed on the screen, and too many are not displayed.

9: The common-base amplifier is a non-inverting amplifier with a large output resistance and a voltage gain of 1, which is called a freewheel.

The common-amplifier is a non-inverting amplifier with a large input resistance and a current gain of 1, which is called a voltage follower.

The common amplifier is an inverting amplifier, and the input and output resistors are between the upper two, and the voltage gain is large and the current gain is also large.

Therefore, the common-source, common-base amplifier knows that the output resistance is large, and the input current is not attenuated to the end of the output resistance. A common set of common, apparently large input resistance, the input resistance is not attenuated to the end of the output resistance.

10: The output average voltage of the sinusoidal voltage is 0.9 times the input voltage rms value in the full-bridge rectifier circuit, so the average value of the output current (equivalent to a multimeter) is 0.9 times the effective value of the input voltage divided by the load resistance.

11: The two probes of the oscilloscope are common ground. When you double track, you should pay attention to these two grounds, especially when it is high voltage! Not all oscilloscopes and two probes are common ground, some The land is independent.

12: The measurement method of the mos tube is generally gds array. To use a multimeter, first power up the gs at both ends, that is, use the multimeter to click gs and then point ds to measure the number. These are judged based on its own characteristics. Note that the capacitance at the gs terminal is small, u=q/c. If it is affected by the outside world, or electrostatically felt, it can make u large and burn it off with a small charge.

13: u disk can not test a lot of small files, and then can not drive, stuck. For example, the IE file, these things are best compressed, and then admitted.

14: Before measuring with a multimeter, you must understand what signal to measure and what gear to use.