Will the digital multimeter replace the analog pointer multimeter?
Here's the English translation highlighting the key differences between digital and analog multimeters:
Key Difference: Internal Resistance
The internal resistance of a digital multimeter (DMM) is two orders of magnitude higher than that of an analog multimeter (AMM). Even the cheapest DMM typically has a higher input impedance than the most expensive AMM. This high impedance minimizes measurement interference, making DMMs more accurate for voltage measurements.
Resistance Measurement Challenges
DMMs supply very low test current (microamps), which is insufficient for quickly charging large capacitors. When measuring leakage resistance in capacitors (e.g., microfarads), DMMs may take too long to stabilize, leading to inaccurate readings.
AMMs provide higher test current (milliamps), allowing them to charge capacitors rapidly. This makes AMMs better suited for testing capacitor leakage.
Advantages of DMMs in Circuit Testing
Online Resistance Measurement: DMMs' low test current minimizes interference from parallel components (capacitors, inductors, transistors), enabling accurate in-circuit resistance measurements without desoldering.
Digital Precision: Ideal for repetitive, high-precision tasks in production and automation.
Why AMMs Still Matter
Nonlinear Component Testing: AMMs deliver test currents closer to real-world operating conditions, making them more reliable for testing PN junctions (diodes, transistors).
Dynamic Circuit Analysis: The moving needle of an AMM provides visual feedback for rapidly changing signals (e.g., voltage fluctuations), which is harder to interpret on a digital display.
Conclusion
While DMMs dominate in production and general-purpose applications, AMMs remain indispensable for circuit debugging, component testing, and scenarios requiring high test current or visual signal tracking. Each tool excels in specific contexts, and professionals often use both for comprehensive diagnostics.
