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