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Subelement E
Digital Logic
Section 33
Types of Logic
What is the voltage range considered to be valid logic low input in a TTL device operating at 5 volts?
  • 2.0 to 5.5 volts.
  • -2.0 to -5.5 volts.
  • Correct Answer
    Zero to 0.8 volts.
  • 5.2 to 34.8 volts.

What is the voltage range considered to be valid logic low input in a TTL device operating at 5 volts?

Zero to 0.8 volts.

From sammylandler:

It makes sense that zero volts would indicate an off or low state. Since there is margin for error, any voltage between zero and 0.8 volts would also be considered low.

Negative voltages are clearly not an option. The other options don't go down to zero, so they are incorrect.


See Wikipedia's article on Transistor–transistor logic

For more information, please see the Electrical 4 U site for the article Transistor Transistor Logic or TTL

Also, see the Sparkfun site for the article Logic Levels by Bri_Huang

And, see the ElProCus site for the article What is Transistor Transistor Logic (TTL) & Its Working


For the overall overview, please see the Electronics Tutorials site for the article Digital Logic Gates

Last edited by markadlerdallas. Register to edit

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What is the voltage range considered to be a valid logic high input in a TTL device operating at 5.0 volts?
  • Correct Answer
    2.0 to 5.5 volts.
  • 1.5 to 3.0 volts.
  • 1.0 to 1.5 volts.
  • 5.2 to 34.8 volts.

What is the voltage range considered to be a valid logic high input in a TTL device operating at 5.0 volts?

2.0 to 5.5 volts.

See Wikipedia's article on Transistor–transistor logic

For more information, please see the Electrical 4 U site for the article Transistor Transistor Logic or TTL

Also, see the Sparkfun site for the article Logic Levels by Bri_Huang

And, see the ElProCus site for the article What is Transistor Transistor Logic (TTL) & Its Working


For the overall overview, please see the Electronics Tutorials site for the article Digital Logic Gates

Last edited by markadlerdallas. Register to edit

Tags: none

What is the common power supply voltage for TTL series integrated circuits?
  • 12 volts.
  • 13.6 volts.
  • 1 volt.
  • Correct Answer
    5 volts.

What is the common power supply voltage for TTL series integrated circuits?

5 volts.

See Wikipedia's article on Transistor–transistor logic

For more information, please see the Electrical 4 U site for the article Transistor Transistor Logic or TTL

Also, see the Sparkfun site for the article Logic Levels by Bri_Huang

And, see the ElProCus site for the article What is Transistor Transistor Logic (TTL) & Its Working


For the overall overview, please see the Electronics Tutorials site for the article Digital Logic Gates

Last edited by markadlerdallas. Register to edit

Tags: none

TTL inputs left open develop what logic state?
  • Correct Answer
    A high-logic state.
  • A low-logic state.
  • Open inputs on a TTL device are ignored.
  • Random high- and low-logic states.

TTL inputs left open develop what logic state?

A high-logic state.

See Wikipedia's article on Transistor–transistor logic

For more information, please see the Electrical 4 U site for the article Transistor Transistor Logic or TTL

Also, see the Sparkfun site for the article Logic Levels by Bri_Huang

And, see the ElProCus site for the article What is Transistor Transistor Logic (TTL) & Its Working


For the overall overview, please see the Electronics Tutorials site for the article Digital Logic Gates

Last edited by markadlerdallas. Register to edit

Tags: none

Which of the following instruments would be best for checking a TTL logic circuit?
  • VOM.
  • DMM.
  • Continuity tester.
  • Correct Answer
    Logic probe.

Which of the following instruments would be best for checking a TTL logic circuit?

Logic probe.

See Wikipedia's articles on:
Logic probe
Transistor–transistor logic

For more information, please see the Electrical 4 U site for the article Transistor Transistor Logic or TTL

Also, see the Sparkfun site for the article Logic Levels by Bri_Huang

And, see the ElProCus site for the article What is Transistor Transistor Logic (TTL) & Its Working


For the overall overview, please see the Electronics Tutorials site for the article Digital Logic Gates

Last edited by markadlerdallas. Register to edit

Tags: none

What do the initials TTL stand for?
  • Resistor-transistor logic.
  • Correct Answer
    Transistor-transistor logic.
  • Diode-transistor logic.
  • Emitter-coupled logic.

What do the initials TTL stand for?

Transistor-transistor logic.

See Wikipedia's article on Transistor–transistor logic

For more information, please see the Electrical 4 U site for the article Transistor Transistor Logic or TTL

Also, see the Sparkfun site for the article Logic Levels by Bri_Huang

And, see the ElProCus site for the article What is Transistor Transistor Logic (TTL) & Its Working


For the overall overview, please see the Electronics Tutorials site for the article Digital Logic Gates

Last edited by markadlerdallas. Register to edit

Tags: none

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