Multimeters & Oscilloscopes

Multimeters and oscilloscopes are enabling the measurement and analysis of electrical signals and parameters in circuits.

Multimeters

Usage

• Voltage Measurement:

  • Measure AC and DC voltage levels in circuits.

• Current Measurement:

  • Measure current flowing through a circuit (both AC and DC).

• Resistance Measurement:

  • Determine the resistance of components and circuits.

• Continuity Testing:

  • Check if there is a complete path for current flow, often with an audible beep.

• Diode Testing:

  • Test the functionality of diodes.

Theory

• Basic Functionality:

  • Multimeters operate based on the principle of Ohm's Law, using a combination of resistors and transistors to measure voltage, current, and resistance.

• Modes:

  • Most multimeters have different modes for measuring voltage, current, resistance, and continuity.

Models:

• Entry-Level

  • ANENG A830L(<$10) : very cheap one from Aliexpress for example, can break though

• Mid-Range

  • crenova ms8223d ($25): Frequently used by myself, very reliable

• High-End

  • Fluke 115 (>$200): very precise, but not really needed if you are not a professional

Oscilloscopes

Usage

• Waveform Visualization:

  • Display and analyze the waveform of electrical signals over time.

• Signal Analysis:

  • Measure parameters like frequency, amplitude, rise time, and signal integrity.

• Debugging

  • Identify issues in electronic designs, such as timing problems or noise in signals.

• Protocol Analysis

  • Analyze digital signals and communication protocols.

Theory

• Basic Functionality

  • Oscilloscopes measure voltage over time and display the results on a screen, usually as a graph. They work by sampling the input signal at high speeds and reconstructing the waveform.

• Components

  • Key components include the vertical amplifier (for voltage), horizontal time base (for time), and triggering system (to stabilize the waveform display).

Models

• Entry-Level

  • PeakTech 1401($200) : Entry level, good reviews

• Mid-Range

  • Rigol MSO5000 Serie ($1000): Used by myself, very reliable

• High-End

  • SDS2000X ($3000): High bandwidth, 2GSa/s sampling rate, large memory depth, but not really needed if you are not a professional

Resources

https://cybergibbons.com/hardware-hacking/sourcing-a-hardware-hacking-toolkit/