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Diode logic is an outdated technology which makes use of diodes to contruct logic gates. Like other logic families, diode logic can be used for construction of boolean logic circuits. Components for these circuits, besides diodes, are resistors and voltage sources. Types of diodes A diode functions as the electronic version of a one-way valve. ...
A logic gate is an arrangement of controlled switches used to calculate operations using Boolean logic in digital circuits. ...
This article needs to be cleaned up to conform to a higher standard of quality. ...
Boolean logic is a system of syllogistic logic invented by 19th-century British mathematician George Boole, which attempts to incorporate the empty set, that is, a class of non-existent entities, such as round squares, without resorting to uncertain truth values. ...
An electrical network or electrical circuit is an interconnection of analog electrical elements such as resistors, inductors, capacitors, diodes, switches and transistors. ...
An ideal resistor is a component with an electrical resistance that remains constant regardless of the applied voltage or current flowing through the device. ...
An ideal voltage source, V, driving a resistor, R, and creating a current I A voltage source is any device or system that produces an electromotive force between its terminals OR derives a secondary voltage from a primary source of the electromotive force. ...
Gate construction
In the following constructions, we use these voltage conventions: - High impedance state or voltage less than zero (ground voltage) equals logic zero.
- Presence of positive voltage (referenced to ground) equals logic One. n logic inputs.
OR gate construction To construct an OR gate with n logic inputs, the following components are required: - n diodes
- Current-limiting resistor
n + 2 electrical nodes are used (counting ground as a node).
The description of the circuit is as follows. All cathodes for every diode are connected to the same node (node 1), a resistor connects node (1) to ground (2), and the remaining n nodes are tge inputs. The output is node (1).
Whenever a logic 1 is present at the anode of one or more diodes, this (these) diode(s) is (are) forward biased, conducting electrical current. Hence, assuming ideal diodes, logic 1 voltage level is present at the output node.
If a logic 0 is present at every anode for every diode, node (1) is held low. Every diode is unbiased or reversed biased.
AND gate construction The following components are required: - n diodes
- Current-limiting resistor
- Positive voltage source
n + 3 electrical nodes are used (counting ground as a node).
The description of the circuit is as follows. All anodes for every diode are connected to the same node (1). A resistor connects node (1) to a positive voltage source (2). Ground is connected to node (3), and the remaining nodes are the inputs. The output is obtained at node (1).
If a logic 1 is present at the cathode of every diode, node (1) is held high by the power supply. Every diode is unbiased (high impedance state or voltage equal to the source voltage) or reversed biased (voltage higher than source voltage).
If a logic 0 is present at any diode, this (these) diode(s) is (are) forward biased, node (1) is held low. This (these) particular diode(s) is (are) forward biased.
NOT gate construction It is not possible to construct a NOT gate using diode logic. A transistor or vacuum tube is required. The NOT gate is a digital logic gate that behaves according to the truth table to the right. ...
Assorted transistors The transistor is a solid state semiconductor device that can be used for amplification, switching, voltage stabilization, signal modulation and many other functions. ...
In electronics, a vacuum tube (U.S. and Canadian English) or (thermionic) valve (outside North America) is a device generally used to amplify, or otherwise modify, a signal by controlling the movement of electrons in an evacuated space. ...
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