When it comes to the ASVAB Electronic Information subtest, don’t feel like you have to know as much as Ben Franklin to get a passing score. Just keep a few basic principles in mind, and use your common sense.
If a question asks, “What’s the safest way to run an extension cord to a reading light?” the answer “across the middle of the floor” is probably going to be wrong.
You can also figure out quite a few answers if you remember these units of measure:
- Current: Amperes (or amps)
- Voltage: Volts
- Resistance: Ohms
- Power: Watts
- Energy: Watt-hours
If you commit the following principles to memory, you’ll have an easier time succeeding on the Electronics Information subtest:
- Ohm’s law: Current = Voltage / Resistance
- Power Watts = Voltage (volts) × Current (amperes) or P = EI.
- Current flows from a negative pole to a positive pole.
- A closed circuit must exist for electricity to flow. (Think NASCAR.)
- Alternating current (AC) changes direction constantly at a constant rate. The number of times a current completes two alternations of direction per second is known as its frequency; the unit of measurement for frequency is the hertz (Hz).
- Electronic devices operate at very high frequencies.
- Electronic devices often require a specific capacitive or inductive reactance to work. Capacitors and inductors are devices used in circuits to provide the type of reactance needed.
- Devices that change alternating current to direct current are called rectifiers.
- A transistor can amplify a signal.
