74LS21 DUAL 4-INPUT AND GATE in Pakistan

These are high-speed silicon-gate CMOS decoders well suited to memory address decoding or data-routing applications. Both circuits feature low power consumption usually associated with CMOS circuitry, yet have speeds comparable to low-power Schottky TTL logic. Both circuits have three binary select inputs (A0, A1, and A2). If the device is enabled, these inputs determine which one of the eight normally high outputs of the HC/HCT138 series goes low or which of the normally low outputs of the HC/HCT238 series go high. Two active low and one active high enables (E1, E2, and E3)are provided to ease the cascading of decoders. The decoder’s eight outputs can drive ten low-power Schottky TTL equivalent loads.

The 7404 is a triple-buffered inverter. It has high noise immunity and the ability to drive 10 LS-TTL loads. The 74HC logic family is functionally as well as pin-out compatible with the standard 74LS logic family. All inputs are protected from damage due to static discharge by internal diode clamps to VCC and ground.

74LS Series ICs are High-Speed Logic gates, ideally a little faster than the 74HC series but more power consumption is required. They are implemented with a Low-Power Schottky diode technology to achieve high switching speed. 74LS148 is one of the 74LS series IC. 74LS148 ICs contain an 8 to 3-Bit priority encoder that converts 8 Data Lines to 3-Line binary. Cascading circuitry (enable input EI and enable output EO) has been provided to allow octal expansion without the need for external circuitry.