Resistance of pulling
Description
A resistance of pulling (or sweater-up resistor) is a resistance in an electronic circuit between the source of food and a line which deliberately brings at the positive state (H or 1 in numerical electronics) this same line. The usual value used for the resistance of pulling is normally of a few kilo Ohm S (ex 4.7 kΩ).
Resistances of pullings are normally used with digital displays to collecting open or when it is undesirable to leave a floating line in a circuit. On the other hand, they increase the energy consumption of the circuit.
The logical level imposed by a resistance of pulling is sometimes called low level since a resistance of pulling cannot provide of current. A level imposed by an active exit or a switch is called strong level. Consequently a strong level with precedence of a low level.
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Use with an open collector
The resistance of pulling is particularly used in the digital circuits called to open collector. Like presents it the diagram, the digital displays of the open collecting type cannot actively be in a raised state, because they cannot provide of current. A resistance of pulling is thus used to raise the exit when it is not on the bottom grade. This technique is used in several digital technologies which require the support of multiple users on a given bus. A concrete example is that of the bus I ² C.
Use with a manual switch
When simple a interruptory mechanical is used like entry with a logical circuit, a resistance of pulling is necessary not to leave floating the entry of the circuit. The resistance of pulling is used in this case to impose the high level while the switch can still impose a bottom grade. Without resistance of pulling, the entry would be floating and thus on an indefinite level logical what could cause an erratic operation of the circuit.
See too
Electronic numerical
References
Mr. Morris Mano, Charles R. Kime, Logic and Computer Design Fundamentals , Third edition, Prentice Hall, New Jersey, 2004,
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