Signals and controls
74HC595 shift register
Set eight digital outputs using three controller pins.
What it does
Data shifts into a register one bit at a time. A separate latch transfers the stored byte to the output pins together.
Connections and compatibility
At 5 V, connect VCC and SRCLR high, GND and OE low, and use data, clock, and latch GPIO signals. Add a nearby 100 nF bypass capacitor.
Choosing one
A DIP-16 74HC595 fits a breadboard. Check the notch and datasheet pin numbering; it is not the same as the 74HC165 input register.
Common mistakes
Outputs have per-pin and total current limits. Use one resistor per LED and a separate driver for relays or motors.
Use it in a tutorial
- Shift registers — Use a 74HC595 to drive eight low-current indicators with three controller pins.