![]() | The component is located in the DISCRETE.LIB library file, so select this file, then select the Resistors - Standard 1/4 Watt - Horizontal, identified by 'RS'. After the selection of the RS' component you will insert the value of the component (47 Kohm), and optionally the Modifier, that is a sub-type component, and the name of the relative component that will be used to make the pcb layout. |
In this case to the R1 component it's been automatically assigned the pcb component called R400P70. The relationship between .SCH and .PCB components is already defined for the standard library Circad components, but this is not true for the newly created user components. For these components the link will be created by the user for every single schematic component.
The label R400P70 means Resistor with 400 mils far pads and 70 mils pads diameter. This is only a remember for the user, in fact if you specify R400P90 you don't obtain a 90 mils component pads, but only an error when the pcb creation, because there are no pcb component pattern (its name) equal to R400P90.
The component R400P70 is included in the THD.LIB standard library file contained in the /Library subdirectory. This library is defined in text mode, so isn't possible to see the pcb shape of the resistor. Then, we'll use the pcb component R400, included into the PCB.LIB standard library, that is the same as the R400P70 component.
To add a special caracter, like the ohm symbol, you must use the combination Alt + code, where the code is a value entered by the numeric keypad. In the table below you'll find the code to use to obtain the most common symbols. Use this mode to insert the symbols in the Windows forms. Else, to insert the symbols when you edit a text use the codes between parenthesis.
1/2 = 0189 (o Alt + 2) | 1/4 = 0188 (o Alt + 4) | 3/4 = 0190 | pigreek = 0182 |
micro = 0181 (o Alt + u) | ohm = Alt + o | +/- = 0177 | >> = 0187 |
<< = 0171 | between = 0247 | diameter = 0216 / 0248 | beta = 0223 |
To see the shape of R1 you must open, with the ![]() |
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After you've placed the component you'll be able to modify some parts of its. In fact,
every element of a Circad file, is an object, also if it's linked to other objects. The label 47Kohm near
R1 is joined with this component (if you move R1 the label will move with R1, but it
does'n happens the contrary), but it's totally indipendent for its characteristics, like
size, layer and rotation. | For example, use ![]() ![]() ![]() |
Now, in the same mode, you'll must place the components R2, D1 and Q1.
You can use the library search method, or directly the pattern available in the
table below. For Q1 you must specify MIOTRAN, a pcb component that doesn't exists in any Circad library file. In the next lessons we will create MIOTRAN, that is the
shape of the pcb component of Q1, that is a BC547 transistor.
The CONN1 component will be placed later... because it doesn't exists and, first, we must create it!
In an electric scheme it's normal to have more than one transistor, every of each
represented, for example, with the shape of an NPN (the schematic pattern of Q1)
transistor, but every component can be associated with a different kind of a
pcb component. If you modify the pcb component shape, direclty into the
library file in witch is contained, when you create the pcb layout, Circad will use the
new modified shape.
Componente | Pattern | Ref. ID | Type/Value | Modifier | PCB Pattern |
R1 R2 D1 Q1 | RS' RS LED NPN | R1 R2 D1 Q1 | 47 Kohm 1 Kohm LED BC547 | 1/4 Watt 1/4 Watt Nothing Nothing | R400 R400 LED MIOTRAN |
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Now you must place the power signal points. It's possible to place positive, negative
or ground signal points. With the ![]() ![]() |