SGDS020D February 2002 – February 2024 SN74AHC74Q-Q1
PRODUCTION DATA
Refer to the PDF data sheet for device specific package drawings
Toggle switches are typically large, mechanically complex and relatively expensive. It is desirable to use a momentary switch instead because they are small, mechanically simple and low cost. Some systems require a toggle switch's functionality but are space or cost constrained and must use a momentary switch instead.
If the data input (D) of the D-type flip-flop is tied to the inverted output (Q), then each clock pulse will cause the value at the output (Q) to toggle. The momentary switch can be debounced and connected through a Schmitt-trigger buffer to the clock input (CLK) to toggle the output.
This application also utilizes a power-on reset circuit so that the output always starts in the LOW state when power is applied.