General exam question G4E10
Subelement G4, AMATEUR RADIO PRACTICES· Group G4E
Why should a series diode be connected between a solar panel and a storage battery that is being charged by the panel?
- A.To prevent overload by regulating the charging voltage
- B.To prevent discharge of the battery through the panel during times of low or no illumination (correct answer)
- C.To limit the current flowing from the panel to a safe value
- D.To prevent damage to the battery due to excessive voltage at high illumination levels
WhyA series diode connected between a solar panel and a storage battery prevents the battery from discharging through the panel during times of low or no illumination. A series diode between a solar panel and the battery it charges only lets current flow from panel to battery, blocking the reverse path the battery would otherwise use to discharge back through the panel whenever the panel's output drops below battery voltage, such as at night, answer B. It isn't there to regulate charging voltage, isn't a current-limiting resistor, and doesn't protect against overvoltage at high illumination, those are the jobs of a charge controller and current-limiting design, not a single series diode.
Published 2026-08-28 · Last updated 2026-08-28 · Question text is verbatim from the 2023-2027 NCVEC Element 3 pool (public domain); the explanation above is original writing, see our methodology.
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