Combinational & Sequential Systems, Circuits, Resistors, Capacitors
Difference Between Combinational and Sequential Systems
Combinational systems are characterized by their outputs, which depend only on the value of their inputs. In sequential systems, the values of the outputs at any given time depend not only on the inputs but also on the state in which they are.
Multiplexer
A multiplexer is a circuit that allows the selection of which of several input data lines should appear on a single output line. Its main application is to send data through a single output line.
Demultiplexers
A demultiplexer has a single input and multiple (n) outputs. It carries data from the input to a specific output according to a given configuration.
Decoders
Decoders are combinational logic circuits built into a single block to transform information encoded in a binary system.
BCD to 7-Segment Decoder
A BCD to 7-segment decoder is capable of providing the data needed to connect to a 7-segment display. For the configuration of a decoder, it is required to provide a high output level.
Encoder
An encoder is a combinational circuit with a series of inputs used to encode digital information.
Electrical Circuits: Resistances
Resistors serve a mission: to oppose the passage of current and transform electrical energy into heat. Resistors play a special role in properly distributing voltage and electrical current.
Tolerance of Resistance
Indicates the maximum and minimum values that fall between the resistance. They are expressed as a percentage of the nominal value in ohms.
Power Dissipation of a Resistor
The greater the power required to work the resistance, the greater the warming. Therefore, there is a risk of burning out if it is not designed properly.
Fixed Resistance
- Agglomerated Resistors: They consist of a mixture of graphite and an insulating material.
- Carbon Film Resistors: These are the most widely used for small powers.
- Metal Film Resistors: These are similar to carbon film resistors, but use a metal alloy film, making them very stable with temperature.
- Wirewound Resistors: They are made by winding resistive wire. Used for high power applications.
Variable Resistors
Variable resistors are used to adjust the electrical parameters of the circuits. Their structure consists of a fixed resistor on a circular support, with a moving cursor or contact.
Light Dependent Resistors (LDR)
LDRs are components that change their electrical resistance according to the light intensity incident on their surface.
Capacitors
A capacitor is a device widely used in electricity. It is a small circuit capable of storing electrical energy and returning it when necessary.
- Utilizing the time it takes to charge, capacitors can be used to build short delays.
- They are used as filters in rectifiers.
- They enable the realization of oscillating circuits and the phenomenon called resonance.
- Removal of interference in broadcasting.
- Power factor correction in AC systems.
Capacitance
The amount of charge a capacitor can store depends on the voltage applied between the plates and its constructive characteristics. Q = C * V
The unit of capacitance is the Farad (F).
Impregnated Capacitors
Impregnated capacitors are manufactured by rolling two sheets of aluminum separated by two sheets of paper impregnated with wax or oil. This increases the size of the capacitor.
Foil Capacitors
Metallic paper is used to avoid the formation of gaps between the plates and the dielectric, minimizing the size.
Plastic Capacitors
Plastic capacitors are widely used. Normally, polyester is used as the dielectric. They have the advantage of achieving relatively high capacity at voltages up to 1000V.
Ceramic Capacitors
Ceramic capacitors use a ceramic composed of a very high dielectric constant. They support little voltage.
Mica Capacitors
Mica capacitors differ significantly from the rest due to their constructive characteristics.