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| 两侧同时换到之前的修订记录 前一修订版 | 上一修订版 两侧同时换到之后的修订记录 | ||
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示波器 [2019/03/10 15:23] gongyu |
示波器 [2019/03/10 15:26] gongyu |
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| 行 36: | 行 36: | ||
| ===探头=== | ===探头=== | ||
| + | |||
| + | =====分类===== | ||
| + | =====主要厂商===== | ||
| + | =====关键指标===== | ||
| + | ====模拟带宽==== | ||
| + | ====采样率==== | ||
| + | ====灵敏度==== | ||
| + | ====动态范围==== | ||
| + | ====存储深度==== | ||
| + | |||
| + | =====主要功能和使用===== | ||
| + | ====探头==== | ||
| Open wire test leads (flying leads) are likely to pick up interference, so they are not suitable for low level signals. Furthermore, the leads have a high inductance, so they are not suitable for high frequencies. Using a shielded cable (i.e., coaxial cable) is better for low level signals. Coaxial cable also has lower inductance, but it has higher capacitance: a typical 50 ohm cable has about 90 pF per meter. Consequently, a one-meter direct (1X) coaxial probe will load a circuit with a capacitance of about 110 pF and a resistance of 1 megohm. | Open wire test leads (flying leads) are likely to pick up interference, so they are not suitable for low level signals. Furthermore, the leads have a high inductance, so they are not suitable for high frequencies. Using a shielded cable (i.e., coaxial cable) is better for low level signals. Coaxial cable also has lower inductance, but it has higher capacitance: a typical 50 ohm cable has about 90 pF per meter. Consequently, a one-meter direct (1X) coaxial probe will load a circuit with a capacitance of about 110 pF and a resistance of 1 megohm. | ||
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| A more-sophisticated probe includes a magnetic flux sensor (Hall effect sensor) in the magnetic circuit. The probe connects to an amplifier, which feeds (low frequency) current into the coil to cancel the sensed field; the magnitude of that current provides the low-frequency part of the current waveform, right down to DC. The coil still picks up high frequencies. There is a combining network akin to a loudspeaker crossover network. | A more-sophisticated probe includes a magnetic flux sensor (Hall effect sensor) in the magnetic circuit. The probe connects to an amplifier, which feeds (low frequency) current into the coil to cancel the sensed field; the magnitude of that current provides the low-frequency part of the current waveform, right down to DC. The coil still picks up high frequencies. There is a combining network akin to a loudspeaker crossover network. | ||
| - | =====分类===== | ||
| - | =====主要厂商===== | ||
| - | =====关键指标===== | ||
| - | ====模拟带宽==== | ||
| - | ====采样率==== | ||
| - | ====灵敏度==== | ||
| - | ====动态范围==== | ||
| - | ====存储深度==== | ||
| - | |||
| - | =====主要功能和使用===== | ||
| - | ====探头==== | ||
| ====耦合和极性==== | ====耦合和极性==== | ||
| ====面板操作==== | ====面板操作==== | ||
| 行 451: | 行 452: | ||
| [[Analog Discovery 2 参考手册]] | [[Analog Discovery 2 参考手册]] | ||
| - | |||