ASVAB Electronics Information: Study Guide and Practice
Circuits, Ohm's law, and components, plus the jobs EI unlocks
July 1, 2026
Electronics Information (EI) is the ASVAB subtest that measures your basic knowledge of electricity and electronics: current, voltage, resistance, Ohm’s law, circuits, and common components. On the CAT-ASVAB you get 16 questions in 8 minutes, about 30 seconds each. EI does not count toward your AFQT, the score that decides whether you can enlist, but it feeds line scores that decide whether you qualify for electronics and technical jobs.
What does ASVAB Electronics Information cover?
EI tests whether you understand how electricity behaves and what basic components do. You do not need to build circuits, but you do need to recognize the core relationships and parts.
| Concept | What to know |
|---|---|
| Current (I) | The flow of electrons, measured in amperes (A) |
| Voltage (V) | The electrical pressure that drives current, measured in volts (V) |
| Resistance ® | Opposition to current flow, measured in ohms (Ω) |
| Ohm’s law | V = I × R, the relationship tying the three together |
| Circuits | Series (one path) versus parallel (multiple branches) |
| AC vs DC | Alternating current reverses direction; direct current flows one way |
Beyond those basics, you should recognize what common components do. Resistors limit current, capacitors store charge, diodes let current flow one direction, and transistors switch or amplify signals.
How is the Electronics Information subtest formatted?
Most recruits take the computer version.
| Version | Questions | Time |
|---|---|---|
| CAT-ASVAB | 16 | 8 min |
| Paper-and-pencil | 20 | 9 min |
The pace is quick, so answer what you know first and make an educated guess on anything that stalls you.
What are the key Electronics Information concepts to review?
These points cover a large share of EI questions.
- Ohm’s law is V = I × R. If you know two values, you can solve for the third.
- Resistance and current are inversely related at constant voltage. Lower resistance means higher current.
- In a series circuit, total resistance is the sum of the resistors and current is the same everywhere. In a parallel circuit, voltage is the same across each branch.
- Silicon is the most common semiconductor. Copper, gold, and silver are conductors, not semiconductors.
- A capacitor stores electrical charge, blocks DC, and passes AC. A diode allows current in only one direction and can convert AC to DC as a rectifier.
- A transformer steps AC voltage up or down using two coils on a shared core. This is how high-voltage line power is reduced for home use.
What does an Electronics Information question look like?
Here is a worked example.
Question. What is the basic unit of electrical resistance? The choices are volt, ohm, ampere, and watt.
Answer. The ohm, symbol Ω. Resistance is measured in ohms, and Ohm’s law defines it as V = I × R. The trap answers each measure something else: the volt measures voltage, the ampere measures current, and the watt measures power. Keeping the units matched to their quantities is half the battle on this subtest.
Which jobs need a strong Electronics Information score?
EI is a component of several Army line scores, which set job eligibility. These subtests build the line scores even though they never touch your AFQT. [NOTE: verify current line score formulas before publishing]
| Army line score | Formula includes EI |
|---|---|
| EL (Electronics) | GS + AR + MK + EI |
| GM (General Maintenance) | GS + AS + MK + EI |
| MM (Mechanical Maintenance) | NO + AS + MC + EI |
Electronics repair, avionics, communications, and general maintenance jobs rely on EI. The Navy, Air Force, Marines, and Coast Guard use their own composites, and many of their most technical ratings weight electronics heavily. Ask your recruiter which line score your target job needs. [NOTE: verify branch-specific composites]
ASVABDRILL is an ASVAB practice test platform focused on AFQT improvement, built for military recruits, covering ASVAB, PiCAT, and verification-style practice.
FAQ
Does Electronics Information count toward my AFQT?
No. Only Arithmetic Reasoning, Mathematics Knowledge, Word Knowledge, and Paragraph Comprehension feed the AFQT. EI affects line scores for electronics and technical jobs, not your enlistment eligibility.
Do I need an electronics background to pass this subtest?
No. EI tests recognition of basic concepts, not hands-on skill. If you can apply Ohm’s law and recognize what a resistor, capacitor, diode, and transformer do, you will handle most of the questions.
How should I study for Electronics Information?
Start with Ohm’s law and the difference between series and parallel circuits, then learn what each common component does. Take an Electronics Information practice test to find your weak spots and read the explanation on every miss.
How many Electronics Information questions are on the ASVAB?
The CAT-ASVAB has 16 questions in 8 minutes. The paper version has 20 questions in 9 minutes.
Related reading
- Complete ASVAB study guide for the full-test plan
- ASVAB line scores explained for how EI feeds job eligibility
- ASVAB mechanical comprehension guide
- ASVAB general science guide
Want to see how your electronics knowledge holds up? Take a full-length ASVAB practice test and check your EI section.