电容的使用：一些经验和误区
一些经验：
在电路中不能确定线路的极性时，建议使用无极电解电容。通过电解电容的纹波电流不能超过其充许范围。如超过了规定值，需选用耐大纹波电流的电容。电容的工作电压不能超过其额定电压。在进行电容的焊接的时候，电烙铁应与电容的塑料外壳保持一定的距离，以防止过热造成塑料套管破裂。并且焊接时间不应超过10秒，焊接温度不应超过260摄氏度。
四个误区：
Read More …
Equipment for most troubleshooting task
- A dual-trace oscilloscope. It’s best to have one with a sensitivity of 1 or 2 mV/cm and a bandwidth of at least 100MHz. Even when you are working with slow op amps, a wide-bandwidth scope is important because some transistors in “slow” applications can oscillate in the range of 80 or 160 MHz. Of course, when working with fast circuits, you should to commandeer the lab’s fastest scope. Sometimes a peak-to-peak automatic triggering mode is helpful.
The Philosophy of Troubleshooting
- There are four basic question that you should ask when you are brought in to do troubleshooting on someone else’ project:
- Did it ever work right ?
- What are the symptoms that tell you it’s not working right?
- When did it start working badly or stop working?
- What other symptoms showed up just before, just after, or at the same time as failure?
- If a OP-AMP circuit’s output were pegged, you should do normally check the the circuit’s op amp, resistors, or conductors. You wouldn’t normally check the capacitors. unless you guessed that a shorted capacitor could cause the output to peg. Conversely, if the op amp’s Vout was a few dozen millionvolts in error, you should start checking the resistors for their tolerances. You might not check for an open circuited or wrong-value capacitor, unless you checked the circuit’ output with a scope and discovered it oscillating!!
-
站点统计
