🔍 Key Concepts

• TTL (Transistor-Transistor Logic) standard logic family voltages • Typical logic ‘HIGH’ and ‘LOW’ levels for TTL • Difference between logic-level voltages and common battery/supply voltages (like 12 V systems)

💭 Think About

• Think about what voltage is typically used to power classic digital logic ICs such as the 74xx series. • Compare each choice to what you know about logic ‘HIGH’ and ‘LOW’ thresholds in TTL – which supply voltage makes those levels practical? • Eliminate any options that are clearly more appropriate for automotive or radio systems rather than small digital logic chips.

✅ Before You Answer

• Verify the standard supply voltage used for 74xx TTL logic families in basic electronics texts. • Check which of the listed voltages would damage a small logic IC if applied directly as Vcc. • Confirm that the chosen voltage matches the typical logic HIGH level being somewhat below the supply voltage for TTL.