AND circuit application circuit diagram analysis
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# AND circuit application circuit diagram analysis

Posted Date: 2024-02-04

AND circuit is also called "logical AND" circuit, the output will become 1 only when all inputs are 1. This circuit can use multiple inputs to fix the output, or to mirror the output. When using switches and LEDs to represent AND circuits, a series circuit can be formed.

In this series circuit, if both switches are on, the LED lights up; if either switch is off, the LED goes off. Basic logic circuits, also called gates, can take a single input to fix the output, or mirror the output.

The application circuit diagram is shown in (a) above: it is an AND circuit composed of ordinary diodes. Input A and B voltage is 5 volts. Here, 5 volts is the high level H, and 0 volts is the low level L. When switches A and L are connected, the voltage of X is 0. As long as one of switch A and switch B is connected to L, the output voltage on X is 0. Only when both switches are switched to H, the voltage of Volt.

When switches A and B are both connected to L, diodes DA and DB are both conductive (because their cathodes are connected to negative electricity, and their anodes are connected to positive electricity through resistor R). When a diode conducts, according to the principles we have learned, we can think of it as a wire. The resistance of light bulb X must be greater than when the diode is turned on, so the current will not pass through X and light bulb X will not light up.

When switches A and B are connected to L and H, only one diode is conducting, so the current will not pass through X and the light bulb X will not light up. When the A and B switches are both connected to H, the cathode of the DA diode is connected to 5 volts, and its anode is connected to 5 volts through the resistor.

The situation is the same for DB diodes and DA. In this case, their negative electrode voltages are higher than their positive electrode voltages, and the diodes are all reverse biased (cut off, since cut off is equivalent to being disconnected). Then the current must pass through the light bulb X, forming a loop. So it lit up.

The advantages of AND circuits mainly include the following points:

High reliability: Since the output of the AND circuit is high level only when all inputs are high level, it has strong resistance to noise and interference and has high reliability.

Good stability: Since the output of the AND circuit does not change with the fluctuation of a single input, it has good stability and does not suffer from excessive fluctuations and noise.

Easy to combine and expand: Since the AND circuit is one of the basic logic gates, it can be combined with other logic gates into more complex circuits to achieve more complex logic functions. This makes AND circuits very convenient when implementing complex control and data processing tasks.

Low power consumption: Since the output of the AND circuit is high only when all inputs are high, it has low power consumption and does not waste too much energy.

Review Editor: Huang Fei

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