Step-by-Step Guide to Using the 74LS93

by lorry in Circuits > Electronics

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Step-by-Step Guide to Using the 74LS93

74LS93 4 Bit Binary Counter.png

The 74LS93 is a 4-bit binary counter, which is a variant of the 7493 but specifically from the LS (Low Power Schottky) TTL family. It can be used to count pulses and as a frequency divider. Here's a step-by-step guide on how to use the 74LS93:

Supplies

Supplies.jpg
  • The 74LS93 IC
  • Breadboard
  • Oscillator or Clock source (to provide the input pulses)
  • Power supply (typically +5V for LS TTL ICs)
  • LEDs (for visual output, optional)
  • Resistors (for LED current limiting, optional)
  • Capacitors (for decoupling, optional)
  • Jumper wires

Set Up the Power

  • Connect pin 14 to the +5V power supply.
  • Connect pin 7 to the ground (0V).

Clock Input

Connect your clock source or oscillator to pin 14. This will provide the pulses that the counter will count.

Reset Pins:

Reset Pins

The 74LS93 has two reset pins: R1 (pin 2) and R2 (pin 3). To ensure the counter starts from zero, momentarily connect these pins to the +5V. These pins should be grounded in regular operation to allow the counter to count. If you want to reset the counter at any point, apply a high signal to both reset pins.

Set Up Output

For visual representation, connect LEDs to the output pins Q_A (pin 12), Q_B (pin 9), Q_C (pin 8), and Q_D (pin 11). Remember to use resistors in series with LEDs to limit the current.

Operating Modes

By default, when you provide clock pulses and with the reset pins grounded, the IC will start counting the pulses in a binary sequence from 0000 to 1111 (0 to 15 in decimal).


If you're using the counter as a frequency divider, you can take the output from one of the Q outputs to get a divided frequency.

Observe the Counting

Electronic Tutorial: A Detailed Tutorial On The 74LS93 Decade Counter IC - Learn To Count In Binary!

With every pulse from your clock source, the LEDs (or your outputs) will change in a binary sequence, indicating the count. For instance, after five pulses, Q_A, Q_B, Q_C, and Q_D will represent the binary for 5, i.e., 0101.

Resetting

To reset the counter back to zero, apply a high signal to both reset pins (R1 and R2).

Safety Decoupling

For stable operation, it's a good practice to connect a small capacitor (like 0.1µF) between the power supply (+5V) and ground, close to the IC. This acts as a decoupling capacitor and prevents potential high-frequency noise on the power line.

Experiment

Play around by changing the frequency of the clock source, or using the counter as a frequency divider, to familiarize yourself with its operations.

Switch Off

Once done, ensure you disconnect the power supply to the circuit.