Practical takeaway
Fixed and variable resistors, capacitors, inductors, fuses, switches, and battery types.
T6A · 11 pool questions
Resistors, Capacitors, Inductors, Switches & Batteries
Fixed and variable resistors, capacitors, inductors, fuses, switches, and battery types.
Technician exam focus
This group contains 11 questions in the current pool. The teaching below keeps the important tested terms visible while explaining what they mean in normal Amateur Radio use.
1. Resistance and adjustment
A resistor opposes current flow in a DC circuit. A potentiometer is a variable resistor and is often used for controls such as volume because changing its resistance changes the signal or voltage delivered to the next stage.
2. Two ways to store field energy
A capacitor stores energy in an electric field and consists of conductive surfaces separated by an insulator. An inductor stores energy in a magnetic field and is commonly made as a coil of wire.
3. Switches and fuses have simple jobs
A switch deliberately opens or closes a circuit. A fuse is a protective device designed to open when excessive current flows. Neither component is there to “improve the signal”; they control or protect the current path.
4. Battery chemistry matters
Common rechargeable chemistries include nickel-metal hydride, lithium-ion, and lead-acid. Carbon-zinc is a common non-rechargeable chemistry. Never assume a battery can be safely recharged just because it looks like another cell of the same size.
T6A checklist
- A resistor opposes current in a DC circuit.
- A potentiometer is an adjustable resistor.
- A capacitor stores energy in an electric field.
- An inductor stores energy in a magnetic field.
- A fuse opens the circuit when excessive current flows.
- NiMH, lithium-ion, and lead-acid are rechargeable; carbon-zinc is not.
Exam scope: NCVEC 2026–2030 Technician Class (Element 2), effective July 1, 2026 through June 30, 2030, with February 19, 2026 errata. The current NCVEC pool is the exam authority; explanatory prose here is SPARKA teaching material. NCVEC pool