Circuit design is an intermediate stage between the beginning of mass production of an electronic product and the idea of creating it, but within the framework of this methodological manual we will go the opposite way, i.e. We will move from an already created device to an understanding of the purpose or idea. We need this because this manual is designed for repairmen of household appliances and electronics, rather than for developers of these devices.
Discrete and integral elements
Any electronic circuit is a set of elements necessary to perform a specific task, for example, amplifying an incoming signal or changing the output voltage. Circuits consist of discrete elements (a single element with one function, such as a resistor or capacitor) and integrated elements (for example, a microcircuit containing many resistors and transistors)
There are two types of circuitry - analog and digital. In digital circuitry there are the concepts of 0 and 1, i.e. if we have +5 volts on the contact (or +3.3 or any other value taken as the reference voltage in the device), then this is conditionally 1, the absence of voltage means we have 0. In analog circuitry, the same +5 volts can have different rise forms noises, etc.that is, we will be interested not only in whether there is voltage or not, we will already be interested in its shape, change over time and other various parameters. For example, a light bulb in a room needs only two states: on and off, while the sound in music speakers needs frequency, depth and volume. Essentially this is the difference between digital and analog circuitry..
Conventionally graphic designation
It is customary to read diagrams from left to right, just like... The numbering of elements is usually done from left to right and from top to bottom. To designate an element on an electrical circuit diagram, UGO is used
All conventional graphic symbols can be divided into standard (typical) and specific, so if we open any environment for drawing circuits, then a resistor, capacitor, etc. will be initially laid out and available there, but sometimes non-standard elements are used in development, which are already drawn for a specific project or scheme.
Elements cannot repeat each other by position designation, so the circuit cannot have several R1 elements, while the values of the elements can be repeated, those in the circuit may have 2.3 or more resistors per 1 KiloOhm (Figure 2), but only one R1 (where R means resistor, and 1 is its serial number)
One of the basic concepts in electrical engineering is BAX (volt-ampere characteristic), which shows the change in current strength from voltage, so for a resistor it will be linear and such elements are called passive, and for a diode it will be in the form of a curve or nonlinear, such elements are called active .
The work of passive elements is subject to Ohm's law, since we have a linear dependence, while active elements have a nonlinear dependence and we can include all semiconductor elements (diodes, transistors, triacs, etc.)
Elements are also divided according to the type of installation, which can be wall-hung, panel or surface-mounted. And the last type of division of radio elements is by purpose, which, depending on the element, can be measuring, antenna, thermoelectric, connecting, acoustic and information.