Thermocouple vacuum gauge teardown and explanation

TL;DR

The video showcases the disassembly of a thermocouple vacuum gauge and how it functions as a low-accuracy measurement tool.

Transcript

hey everyone I just picked up this thermocouple vacuum gauge on eBay and I thought I'd take it apart and show you how it works so the idea is that you connect this box up to one or two of these and this is a thermocouple vacuum gauge which I'll talk about in a minute and right now I have another one of these connected into this manifold and then th... Read More

Key Insights

• ✋ Thermocouple vacuum gauges are not highly accurate but are helpful in determining if a high vacuum device can be turned on.
• ✊ The disassembled thermocouple vacuum gauge reveals a simple circuit design with an unregulated power source and a variable resistor for current control.
• 🎭 The thermocouple vacuum gauge utilizes a four-wire system with two wires connected to a heater and a thermocouple to measure the heat loss in a vacuum.
• 🤒 The vacuum gauge's meter utilizes a diode and a capacitor to convert the AC current to DC for accurate readings.
• 🎨 The design of older thermocouple vacuum gauges differs significantly from modern electronic designs, showcasing the evolution of technology.
• 😚 Safety precautions should be taken when handling the live current in the gauge, as it passes through close proximity to grounded posts.
• 🧑‍🏭 The accuracy of the thermocouple vacuum gauge can be affected by factors such as the rubber hose used in the connection.

Questions & Answers

Q: How does a thermocouple vacuum gauge work?

The vacuum gauge utilizes a four-wire system with two wires connected to a heater and a thermocouple. When the vacuum is present, the heater gets hot, causing the thermocouple to produce a small voltage.

Q: Are thermocouple vacuum gauges accurate?

Thermocouple vacuum gauges are not known for high accuracy but are useful in determining if a high vacuum device can be activated.

Q: How is the current controlled in the thermocouple vacuum gauge?

The current is controlled by an unregulated power source and a variable resistor. The resistance of the heater and a 30-ohm resistor determine the amount of current flowing through the circuit.

Q: Why does the thermocouple vacuum gauge have two sensor ports?

The gauge is designed to accommodate two sensors, but in the disassembled unit, it was discovered that the two heaters were incorrectly wired in parallel, rendering the readings inaccurate.

Summary & Key Takeaways

• The video demonstrates the use of a thermocouple vacuum gauge connected to a digital gauge to measure the vacuum level.

• Thermocouple vacuum gauges are not highly accurate but are helpful in determining if a high vacuum device can be turned on.

• The disassembled gauge reveals a simple circuit design using a power source, variable resistor, and a meter.