4 Bit Up/Down Counter 74191

The 4 Bit Up/Down Counter 74191 is a synchronous, presettable 4-bit binary counter that counts up or down between 0 and 15. A single clock input drives all four flip-flops at once, a direction pin selects up or down counting, and parallel load inputs let you preset any starting value, which makes it useful for timers, dividers and digital control circuits.

4 Bit Up/Down Counter 74191 Specifications

• Function: synchronous 4-bit binary up/down counter (0–15)
• Clock: pin 14, counts on the rising edge
• Control inputs: down/up pin 5 (LOW = up), count enable pin 4 (active LOW), load pin 11 (active LOW)
• Data inputs: A, B, C, D on pins 15, 1, 10, 9
• Outputs: QA, QB, QC, QD on pins 3, 2, 6, 7
• Cascade outputs: max/min pin 12, ripple clock pin 13
• Power: VCC pin 16, GND pin 8, 5 V logic

4 Bit Up/Down Counter 74191 Applications

• Up/down counters for push buttons and rotary encoders
• Programmable frequency dividers
• Presettable countdown timers
• Cascaded counters for 8-bit or larger counts
• Digital logic labs and university courses

What's in the Box

• 1 × 74191 4-bit up/down counter IC

Tip: Hold the enable pin LOW to count and keep the load pin HIGH, since pulling it LOW copies the A–D inputs straight to the outputs. To cascade two counters, connect the ripple clock output of the first to the clock input of the next, and decouple each IC with 100 nF.

Orders placed before 14:00 are ready for pickup the same day. Delivery across Lebanon usually takes 1–3 working days.