DATASHEET and Circuit Diagram

A schematic described Resistor Color Code and Chart Diagram appears in the following illustration. Resistor is such a device for a two-terminal electronic component that produces a voltage  across its terminals that is proportional to the electric current passing through it in accordance with Ohm’s law (wikipedia.org).

This electronic color code was developed in the early 1920s. In the Resistor Color Code and Chart, Resistor values are always coded in Ohms. The chart outlines resistor color code (black, brown, red, orange, yellow green, blue, violet, grey, white, and gold), 4/5-Bands Code (1st, 2nd, 3rd, multiplier and tolerance).

Battery backup and battery charging are two modes of battery backup circuits. The circuit below shown a simple battery backup circuit using low treshold MOSFET device in order to gain better efficiency in addition of very low voltage drop resulted by the MOSFETs that will prolong battery life, and meet battery voltage limitations.

You require the following component selection to design this Battery Backup Circuit : 1N4001 Diodes (D1-D5), standard 1/4 watt, 5% tolerance Resistors, dual comparator LM393N for U1, 5 Eveready nickel cadmium cells battery in series, and TN0604N3 low threshold N-channel DMOS transistors for their low on-resistance at low gate drive. You can modify this circuit with an added features such as battery backup mode indicator, low battery voltage early warning, or battery shutdown indicator with a microprocessor in more complex systems.

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Article about STMicroelectronics M74HC51 CMOS Datasheet below describes that the M74HC51 is an high speed CMOS DUAL 2 WIDE 2 INPUT and/or INVERT GATE fabricated with silicon gate C2MOS technology and many other characteristics of this device.

The internal circuit is composed of 3 stages (2 INPUT) or 5 stages (3 INPUT) including buffer output, which enables high noise immunity and stable output. All inputs are equipped with protection circuits against static discharge and transient excess voltage, accordingly.  The M74HC51 consist of three pakcage of order code types such DIP (M74HC51B1R), SOP (M74HC51M1R, M74HC51RM13TR), and TSSOP (M74HC51TTR).

There are  diagrams viewed clearly such I/O Equivalent Circuit, PIN description with named and functions of each number and also truth table with all other combinations within. The M74HC51 featured High Speed, Low Power Dissipation, High Noise Immunity, Symmetrical Output Impedance, Wide Operating Voltage Range, etc. It also contains mechanical data tables of each type of this device.

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