Sure enough, there are three basic dependent sources. Ltspice guide click on the swcad iii shortcut created by the software installation. Tstep is the printing increment, and tstop is the final time. In the above figure, the voltage across the source terminal v ab is dependent on the voltage across the terminal v cd. Accurate spice compatible cnt interconnect and cntfet. What is independent dependent voltage and current source. Hspice is a smart program and will automatically assign ohms to resistors, farads to capacitors, and henries to inductors. In pspice, this can be done using the etable component in the 2015 oxford university press reprinting or distribution, electronically or otherwise, without the express written consent of oxford university press is prohibited. In the theory of electrical networks, a dependent source is a voltage source or a current source whose value depends on a voltage or current elsewhere in the network dependent sources are useful, for example, in modelling the behavior of amplifiers. Consider the pulse voltage source in the above image, with the following characteristics. A current source dependent on the current of a voltage source. So far we have covered circuits with resistors and independent sources.
Jul 30, 2017 creating a current source in lt spice. Modeling voltagecontrolled resistors and capacitors in. There are three types of voltage dependent current source circuit elements. Using positive current convention, current flows out from the first node, through the circuit and then into the second node. The first two examples specify a dc voltage source of 5 v connected between node 1 and ground. Using pspice to find the thevenin equivalent circuit. Because the version 1 is a voltage source, it doesnt need a dummy resistor to ground, like version 2, when driven by a current source. Circuit elements and models university of california, berkeley. There are three types of voltage dependent currentsource circuit elements. Pspice voltagedependent, voltage source eeweb community.
Voltage sources, in addition to being used for circuit excitation, are the ammeters for spice, that is, zero valued voltage sources may be inserted into the circuit for the purpose of measuring current. The electrical source is of two types namely independent source and dependent source. Ltspice iv getting started guideltspice iv getting started. A bipolar junction transistor can be modelled as a dependent current source whose magnitude depends on the magnitude of the current fed into its. The convention here is that positive current flows in to the positive terminal. In this example the dependent voltage source is called esource and the positive terminal of the source is net 3. As discussed in class there are four types of dependent sources, two are voltage sources and two are current sources. Using basic electrical units, the following examples are easy to understand. Measure current to measure the current through a component, move the mouse cursor over the component and click. Star hspice independent source functions using sources and stimuli 58 star hspice manual, release 1998. Cccs is a star hspice keyword and should not be used as a node name. To allow us to set the transconductance factor of the source to the noise density in favhz, we need a resistor with a noise density of 1 fvvhz, which means that the resistor shall have the very small value of 60.
Note that the voltage across resistor r3 is expressed as v0. The independent and dependent source means, whether the voltage or current sources are either depending upon some other source, or they are acting independently. This element facilitates the adjustment of propagation. The delay element is the same as a current controlled current source except it is associated by a propagation delay td.
In the theory of electrical networks, a dependent source is a voltage source or a current source whose value depends on a voltage or current elsewhere in the network. Both upper and lower case letters are allowed in pspice and hspice. Voltage dependent voltage current dependent current lossy transmission line bipolar transistor current dependent current voltage controlled switch voltage dependent current current dependent voltage independent current source lossless transmission line uniform rcline independent current source independentvoltagesource jfet transistor mutual. Hspice is just a program that takes in a netlist a simple text. The current source b1 depends on i1 which is the current in the source branch v1r1. This can be modelled using a voltagecontrolled current source with voltage controlled by tablebased voltagecontrolled current source.
Using pspice for circuits with dependent sources the problems in this tutorial and the corresponding homework continue to deal with the dc analysis of circuits, or dc bias analysis in pspice. Ltspice iv getting started guideltspice iv getting started guide. Starting with spice3, they allowed a v for voltage or an i for current. It isnt difficult to make an incorrect assumption based on this. Note that the third mesh current i 3 is strictly dependent upon the voltage v x via ohms law with the 4r resistor. The university of evansville ltspice iv component library. Aug 30, 2009 sure enough, there are three basic dependent sources. Instead of this algebraic notation the ue library voltagedependent symbols include a pair of terminals that. This tutorial introduces the dependent source elements in pspice. The max and min parameters specify a maximum e1 voltage of 5 v and a minimum e1 voltage output of 5 v. The voltage applied is equal to the value of the gain times the current through the voltage source. R ohm c farad l henry the scaling for the all units in hspice is done by. This function can include nodal voltages, element currents, time, or user defined parameters. Dont leave it float, neither connect it to a voltage source directly.
Likewise, you can make it current dependent by entering vipart. Accurate spice compatible cnt interconnect and cntfet models. Download pspice for free and get all the cadence pspice models. This equation would be the additional constraint on the mesh currents implied by the current source, namely i 2 i 3 ki 1.
On the other hand, you couldnt connect version 1 directly across a voltage source. Hspice simulation and analysis user guide version x2005. The current that controls the value of the controlled source flows through the voltage source named vsens to use a current controlled current source, a dummy independent voltage source is often placed into the path of the controlling current. Instead of this algebraic notation the ue library voltage dependent symbols include a pair of terminals that. This can be modelled using a voltage controlled current source with voltage controlled by tablebased voltage controlled current source. The first example describes a current controlled current source connected between nodes and 5. However, the voltage source value is proportional to two other signals in the circuit two net voltage in the circuit, say net a and net b. Iname n1 n2 type value n1 is the positive terminal node n2 is the negative terminal node type can be dc, ac or tran, depending on the type of analysis see control statements value gives the value of the source the name of a voltage and current source must start with v and i, respectively. As an example, one can specify a capacitor of 225 picofarad in the following ways. Note the value for e1 is expressed in terms of an unknown value. Hspice tutorial university of california, berkeley.
Use the macromodels shortcuts to download the datasheet as a reference for yygour design. However, it is not written that you must trust hspice and so the units can be manually assigned by. Ac sources ac current and voltage sources are impulse functions used for an ac analysis. The source which supplies the active power to the network is known as the electrical source. Adding a current dependent voltage source to ltspice. Vpulse pulse voltage source model online documentation. The above method will measure voltage with respect to ground.
Source controlled multiple controlling sources voltage source. However, to get around this problem go back to the schematic. Ltspice dependent voltage sources circuit electrical. Abs output is absolute value if abs1 cccs keyword for current controlled current source. Sep 15, 2011 this equation would be the additional constraint on the mesh currents implied by the current source, namely i 2 i 3 ki 1. Voltage controlled current source vccs in the voltage controlled current source, the current of the source i ab depends on the voltage across the terminal cd v cd as shown in the figure below. Input bias current ib and input offset current ios. H current dependent voltage source ltwikiwiki for ltspice. Now, you will be shown a window with only the dependent source. Im trying to create a current dependent current source and im really stuck.
Google search suggested either i iv1 or i ir1, but neither of those gave the correct answer. In the first example here, the convention makes the dependent source s current flow opposite the direction its arrow is pointing. A and v th 3 v, the series resistor value is selected as r s 20 k using eq the inputoutput voltage plot is given in fig. A nodal analysis with a dependent source occurs when there are two dc voltage sources and a dc current source as shown in figure 1. The third and fourth examples specify a 5 ma dc current source between node 1 and ground. For a dc voltage source, enter the voltage and series resistance.
The operation of the voltage regulator circuit is also verified by hspice simulations. Next to a dependent voltage source you might see notation like 100 va for a voltage dependent source or 20 ib for a current dependent source. In the first example here, the convention makes the dependent sources current flow opposite the direction its arrow is pointing. Spice compatible cnt interconnect and cntfet models are presented in this work. For the sources, the qualifer input is dc, ac, or a transient function as applicable to the respective analysis. Most elementary math functions are allowed and you can use node voltages and terminal currents in. How to model a voltage controlled switch in hspice. Spice quick reference sheet the general anatomy of a.
The four types of dependent sources are listed below in table 1 along with their abbreviation, pspice name and library. The b source is a type of nonlinear controlled source that was added to open the door to pretty much any function you might want, covering pretty much all possible cases. Simulation with hspice university of texas at dallas. The gain can be either a positive or negative gain. The simulationready pulse voltage source component vpulse can be found in the simulation sources integrated library \library\simulation\simulation sources. A voltage source is like a battery, or labbench power supply. Open the symbol and put a gain value in for value 1 2. Using pspice for circuits with dependent sources the problems in this tutorial and the corresponding homework continue to deal with the dc. Cccs is a starhspice keyword and should not be used as a node name. I have a voltage source, say vs, that will be used as a supply voltage for the circuit. Current dependent voltage source in ltspice youtube.
A good example of this is a vco where control is the input voltage node and osc is the oscillator output. This would create a voltage loop forcing spice to stop and reprimand you for breaking the rules. Figure 1 above shows an example of a circuit with a current controlled voltage source. To see the voltage at node 2 change, you can connect node 2 to a current source, or to a voltage source by a resistor. Ltspice tips current dependent current source motley. I think that the first suggestion would be simpler. Note that the voltage across resistor r1 is expressed as vx.
Starhspice independent source functions using sources and stimuli 58 starhspice manual, release 1998. I am wondering if there is a way to do the following. To measure voltage across a component, click on the positive node to be measured, drag the mouse to the negative node and release the mouse. Next to a dependent voltage source you might see notation like 100 va for a voltagedependent source or 20 ib for a currentdependent source. Average and rms voltagecurrent after selecting a voltage or. Nodal analysis and dependent sources technical articles. Getting started using ltspice ivgetting started using ltspice iv. Open a new pspice project and enter this schematic. I os where i b and i os are, respectively, the input bias current and the input offset current specified by the opamp manufacturer. Open the symbol and type vvnode into value, it will output the voltage at node. Ltspice current dependent current source all about circuits.
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