Study › Amateur Extra › E7A › E7A02

E7A02

PRACTICAL CIRCUITS · Digital circuits: digital circuit principles and logic circuits; classes of logic elements; positive and negative logic; frequency dividers; truth tables

E7A02E7A →

What is the function of a decade counter?

  1. AIt produces one output pulse for every 10 input pulses
  2. BIt decodes a decimal number for display on a seven-segment LED display
  3. CIt produces 10 output pulses for every input pulse
  4. DIt decodes a binary number for display on a seven-segment LED display
Why A decade counter is a divide-by-10 frequency divider: it counts input pulses from 0 through 9 and then rolls over, generating one carry/output pulse for every ten pulses at its input. "Decade" means ten, so the output frequency is the input frequency divided by 10. Cascading decade counters gives divide-by-100, divide-by-1000, and so on, which is how frequency counters build their decimal display chain.
Watch out The choices about driving a seven-segment display describe a BCD-to-seven-segment decoder/driver, a separate chip that often follows a decade counter; and no simple counter multiplies pulses, so producing 10 outputs per input is backwards.
Decade = 10. Counters divide, never multiply: 10 in, 1 out.
HamSandwich explanation, first draft. The question and answers are the NCVEC text.
← E7A01 All of E7A E7A03 →

The rest of E7A

  1. E7A01 Which circuit is bistable?
  2. E7A02 What is the function of a decade counter?
  3. E7A03 Which of the following can divide the frequency of a pulse train by 2?
  4. E7A04 How many flip-flops are required to divide a signal frequency by 16?
  5. E7A05 Which of the following circuits continuously alternates between two states without an external clock signal?
  6. E7A06 What is a characteristic of a monostable multivibrator?
  7. E7A07 What logical operation does a NAND gate perform?
  8. E7A08 What logical operation does an OR gate perform?
  9. E7A09 What logical operation is performed by a two-input exclusive NOR gate?
  10. E7A10 What is a truth table?
  11. E7A11 What does "positive logic" mean in reference to logic devices?
Nagoya NA-771 Dual Band Handheld AntennaSponsored · View on Amazon →Icom IC-7300 HF/50MHz Base TransceiverSponsored · View on Amazon →