What Do We Use to Measure Current?

TL;DR

Explaining the use of moving coil galvanometer and oscilloscope for measuring current, including direct and alternating currents.

Transcript

hi i'm steve jones and i'm going to explain what we use to measure current now current uh will describe as direct current for the moment for direct current life is quite easy and these instruments have been with us for hundreds of years or at least a couple hundred years basically it's a little bit like an electric motor we have a coil and we have ... Read More

Key Insights

• 😒 Moving coil galvanometers use a coil and magnetic field to measure direct current.
• 💱 Alternating current requires an oscilloscope for accurate measurement due to its changing direction.
• ❣️ The oscilloscope displays current signals using x and y plates on a screen.
• ⚡ Voltage measurements can be correlated to current measurement using resistance.
• ❓ Moving coil galvanometers have been trusted for current measurement for centuries.
• 💻 An oscilloscope functions similarly to a TV screen in displaying current signals.
• ⚡ The sawtooth voltage applied to the oscilloscope controls the movement of the signal on the screen.

Questions & Answers

Q: How does a moving coil galvanometer measure direct current?

A moving coil galvanometer utilizes a coil and a magnetic field to measure the current's strength, with the coil turning based on the current passing through. The pointer on the coil indicates the current value on a scale.

Q: Why can't a moving coil galvanometer measure alternating current effectively?

Alternating current changes direction rapidly, causing the coil in a moving coil galvanometer to remain stationary at zero. Thus, a different device like an oscilloscope is needed to measure alternating current accurately.

Q: What is the role of an oscilloscope in measuring alternating current?

An oscilloscope uses x and y plates to display the alternating current signal on a screen, with a sawtooth voltage applied to move the spot left and right. This enables the visualization of alternating current signals.

Q: How is current measured using an oscilloscope?

While an oscilloscope primarily measures voltage, the relationship between voltage, current, and resistance allows for the measurement of current by displaying the current signal on the screen.

Summary & Key Takeaways

• Steve Jones explains the use of moving coil galvanometer for measuring direct current using a coil and field magnets.

• To measure alternating current, an oscilloscope is used with x and y plates to display the current signal on a screen.

• The relationship between voltage, current, and resistance enables accurate current measurement using these devices.