Unit 1 — Theory of Operation
TM-CAL-014 — Open Handout TM Chapter: Chapter 2 ELOs: Understand how the reference standard generates or maintains its reference value; identify key specifications Estimated time: 20 minutes
Step 1: Read the TM
Open TM-CAL-014. Read Chapter 2 — Theory of Operation completely.
Then come back here.
Chapter 2 Content
2-1. RESISTIVE LOAD PRINCIPLE
Power delivered to a resistive load equals P = V2/R = I2R. For a 50 Ω load driven by an RF source matched to 50 Ω:
Power from RMS voltage
P (W) = VRMS2 / 50
RMS voltage for given power
VRMS = √(P × 50)
| Power (W) | VRMS (V) | Vpeak (V) | IRMS (A) |
|---|---|---|---|
| 0.1 | 2.24 | 3.16 | 0.045 |
| 1.0 | 7.07 | 10.0 | 0.141 |
| 5.0 | 15.8 | 22.4 | 0.316 |
| 10.0 | 22.4 | 31.6 | 0.447 |
| 100.0 | 70.7 | 100.0 | 1.41 |
Why Theory Matters for Calibration
You cannot calibrate what you do not understand. Theory tells you: - What the instrument or standard is supposed to do — so you recognize when it is not doing it - What the sources of error are — so you know which ones your calibration procedure addresses - What the limits of the calibration are — so you know when to stop and call it good
If a calibration measurement produces a surprising result, theory is where you look first.
Self-Check Questions
SC1-1. In one sentence, state the operating principle of the 50-OHM DUMMY LOAD POWER STANDARD as described in Chapter 2.
SC1-2. What does Chapter 2 identify as the primary source(s) of measurement error or uncertainty?
SC1-3. What key specification(s) (accuracy, range, resolution) does the TM state for this standard?
SC1-4. What safety precaution does §1-3 specify? State it exactly.
SC1-5. What references does §1-2 cite? List at least two.
Answer Key
SC1-1. See TM §2-1. Compare your sentence to the first substantive paragraph of Chapter 2.
SC1-2. See Chapter 2. Look for language about error sources, uncertainty, drift, or limiting factors.
SC1-3. See Chapter 2. Look for numbers with units: %, ppm, Hz, Ω, dB.
SC1-4. See TM §1-3. Copy the safety text exactly.
SC1-5. See TM §1-2. The references list is there.
Checkpoint
Before proceeding, state without looking: - The operating principle of the 50-OHM DUMMY LOAD POWER STANDARD - The primary error source(s) - At least one key specification with its value
→ Proceed to Unit 2