Digital Electronics: Principles, Devices and Applications

Logic Families 143Figure 5.25Handling unused inputs of OR and NOR gates.capacitor is also known by the name of power supply decoupling capacitor, and it is recommendedto use a separate capacitor for each IC. A decoupling capacitor is connected as close to the V CCterminal as possible, and its leads are kept to a bare minimum to minimize lead inductance. Inaddition, a single relatively large-value capacitor in the range of 1–22 F is also connected betweenV CC and ground on each circuit card to take care of any low-frequency voltage fluctuations in thepower supply line.Example 5.5Refer to Fig. 5.30. Determine the current being sourced by gate 1 when its output is HIGH and sunkby it when its output is LOW. All gates are from the standard TTL family, given that I IH = 40 A andI IL = 1.6 mA.