Programming instructions
Digital Power Supplies
National Instruments Corporation 1-3 Multisim Component Reference Guide
A single cell has a voltage of approximately 1.5 volts, depending on its construction. It
consists of a container of acid in which an electrode is placed. Chemical action causes
electrons to flow between the electrode and the container, and this creates a potential
difference between the electrode and the material of the container.
Batteries can be rechargeable and can be built to deliver extremely high currents for long
periods. The automobile ignition battery is an application of a battery as a “current source”;
the voltage may vary considerably under use, with no visible battery deterioration.
Batteries may be used as voltage references, their voltage remaining stable and predictable to
many figures of accuracy for many years. The standard cell is such an application. A standard
cell is a voltage source, and it is important that current is not drawn from the standard cell.
Battery Component
Multisim includes both an ideal battery (DC_POWER), with no internal resistance and a non-
ideal battery, that allows you to changes its internal resistance and capacity (in ampere hours).
1.4 Digital Power Supplies
The Power Source component family includes the digital power supplies VCC, VDD, VEE,
and VSS. These are used to connect power to digital components which do not have an
explicit power pin on their symbol. They can also be wired directly into a circuit as desired.
Tip If you are unsure of the power supply required for a digital component that has its power
pin hidden, double-click on the component and click on the
Pins tab. Locate the power
supply in the
Name column. Some components, will have more than one power supply
(for example, a CMOS 4522BD has both VDD and VSS).
When you connect a wire to a digital power supply (for example, VCC), the wire’s net name
will be the same as the digital supply’s RefDes (so in the case of VCC, the net name will be
V
CC). Multiple instances of a digital power supply may be placed on a schematic but there
will only be one matching net in the schematic. Also, when you change a digital power
supply’s voltage, the voltage for all instances of that power supply on the schematic will
change to reflect the new setting.
ComponentRef.book Page 3 Thursday, December 7, 2006 10:12 AM