CIRCU124 ## CIRCU124 Element Description

## CIRCU124 Input Data

### CIRCU124 Input Summary

## CIRCU124 Output Data

## CIRCU124 Assumptions and Restrictions

**Electric
Circuit**

Compatible Products: – | – | – | Enterprise | Ent PP | Ent Solver | –

CIRCU124 is a general circuit element applicable to circuit simulation. The element has up to 6 nodes to define the circuit component and one or two degrees of freedom per node to model the circuit response. CIRCU124 can be directly coupled to the electromagnetic or stranded coil analysis options of PLANE233, SOLID236, and SOLID237 through the VOLT degree of freedom. CIRCU124 is applicable to static, harmonic, and transient analyses.

The geometry, node definition, and degree of freedom options are shown in Figure 124.1: CIRCU124 Circuit Element Options (circuit components) and Figure 124.2: CIRCU124 Circuit Source Options (circuit source
options). The element is defined by *active* and *passive* circuit nodes.* Active* nodes
are those connected to an overall electric circuit, and *passive* nodes are those used internally by the element and not connected to the
circuit.

Element circuit components and sources are defined by KEYOPT(1) settings and its corresponding
real constants. Real constant input is dependent on the element circuit option used. A summary of
the element input options is given in "CIRCU124 Input Summary". Real constants numbers 15 and
16 are created by the GUI Circuit Builder (see the *Modeling and Meshing Guide*), and are not required input for
analysis purposes. The element is characterized by one or two degrees of freedom:

VOLT (voltage)

CURR (current)

Independent voltage and current sources (KEYOPT(1) = 3 or 4) may be excited by AC/DC, sinusoidal, pulse, exponential, or piecewise linear load functions as defined by KEYOPT(2); see Figure 124.3: Load Functions and Corresponding Real Constants for Independent Current and Voltage Sources.

The time-step size for a transient analysis is controlled by the **DELTIM** or
**NSUBST** commands. The CIRCU124 element does not
respond to automatic time stepping (**AUTOTS** command), but
**AUTOTS** can be used as a mechanism for ramping the time step to its final
value. For coupled electromagnetic-circuit problems, automatic time stepping may be used if
controls are placed on degrees of freedom other than VOLT or CURR, or loads associated with those
degrees of freedom.

For problems using the CIRCU124 element, the sparse direct solver is chosen by default.

**Nodes**I, J, K, L, M, N

**Degrees of Freedom**VOLT, CURR (see Figure 124.1: CIRCU124 Circuit Element Options)

**Real Constants**Dependent on KEYOPT(1) and KEYOPT(2) settings. See Table 124.1: CIRCU124 Real Constants for details.

**Material Properties**None

**Surface Loads**None

**Body Loads**See KEYOPT(2)

**Special Features**None

**KEYOPT(1)**Circuit component type:

**0 --**Resistor

**1 --**Inductor

**2 --**Capacitor

**3 --**Independent Current Source

**4 --**Independent Voltage Source

**8 --**Mutual Inductor

**9 --**Voltage-Controlled Current Source

**10 --**Voltage-Controlled Voltage Source

**11 --**Current-Controlled Voltage Source

**12 --**Current-Controlled Current Source

**KEYOPT(2)**Body loads available if KEYOPT(1) = 3 or 4:

**0 --**DC or AC Harmonic load

**1 --**Sinusoidal load

**2 --**Pulse load

**3 --**Exponential load

**4 --**Piecewise Linear load

**Table 124.1: CIRCU124 Real Constants**

Circuit Option and Graphics Label | KEYOPT(1) | Real Constants | |||
---|---|---|---|---|---|

Resistor (R) | 0 | R1 = Resistance (RES) | |||

Inductor (L) | 1 |
| |||

Capacitor (C) | 2 |
| |||

Mutual Inductor (K) | 8 |
| |||

Independent Current Source (I) | 3 | For KEYOPT(2) = 0:
| |||

Voltage-Controlled Current Source (G) | 9 | R1 = Transconductance (GT) | |||

Current-Controlled Current Source (F) | 12 | R1 = Current Gain (AI) | |||

Independent Voltage Source (V) | 4 | For KEYOPT(2) = 0:
| |||

Voltage-Controlled Voltage Source (E) | 10 | R1 = Voltage Gain (AV) | |||

Current-Controlled Voltage Source (H) | 11 | R1 = Transresistance (RT) |

**Note:** For all above Circuit options, the
GOFFST and ID real constants (numbers 15 and 16) are created by the
Circuit Builder automatically:

**Figure 124.3: Load Functions and Corresponding Real Constants for Independent
Current and Voltage Sources**

The element output for this element is dependent on the circuit option selected. Table 124.2: CIRCU124 Element Output Definitions summarizes the element output data.

**The Element Output Definitions table uses
the following notation:**

A colon (:) in the
Name column indicates that the item can be accessed by
the Component Name method (**ETABLE**, **ESOL**). The O column indicates the availability of the items in the file **Jobname.OUT**. The R column indicates the availability of
the items in the results file.

In either the O or R columns,
“Y” indicates that the item is *always* available, a number refers to a table footnote
that describes when the item is *conditionally* available, and “-” indicates that the item is *not* available.

**Table 124.2: CIRCU124 Element Output Definitions**

Name | Definition | O | R |
---|---|---|---|

For KEYOPT(1) = 0: Resistor | |||

EL | Element Number | Y | Y |

NODES | Nodes - I, J | Y | Y |

RES | Resistance | Y | Y |

VOLTAGE | Voltage drop between node I and node J | Y | Y |

CURRENT | Current | Y | Y |

POWER | Power loss | Y | Y |

For KEYOPT(1) = 1: Inductor | |||

EL | Element Number | Y | Y |

NODES | Nodes - I, J | Y | Y |

IND | Inductance | Y | Y |

IL0 | Initial current | Y | Y |

VOLTAGE | Voltage drop between node I and node J | Y | Y |

CURRENT | Current | Y | Y |

POWER | Power absorption | Y | Y |

For KEYOPT(1) =
2: Capacitor | |||

EL | Element Number | Y | Y |

NODES | Nodes - I, J | Y | Y |

CAP | Capacitance | Y | Y |

VC0 | Initial voltage | Y | Y |

VOLTAGE | Voltage drop between node I and node J | Y | Y |

CURRENT | Current | Y | Y |

POWER | Power absorption | Y | Y |

For KEYOPT(1) = 3: Independent Current Source | |||

EL | Element Number | Y | Y |

NODES | Nodes - I, J | Y | Y |

CURRENT SOURCE | Real or imaginary component of applied current | Y | Y |

VOLTAGE | Voltage drop between node I and node J | Y | Y |

CURRENT | Current | Y | Y |

POWER | Power (loss if positive, output if negative) | Y | Y |

For KEYOPT(1) = 4: Independent Voltage Source | |||

EL | Element Number | Y | Y |

NODES | Nodes - I, J, K | Y | Y |

VOLTAGE SOURCE | Real or imaginary component of applied voltage | Y | Y |

VOLTAGE | Voltage drop between node I and node J | Y | Y |

CURRENT | Current at node K | Y | Y |

POWER | Power (loss if positive, output if negative) | Y | Y |

For KEYOPT(1) = 8: 3-D Mutual Inductor (Transformer) | |||

EL | Element Number | Y | Y |

NODES | Nodes - I, J, K, L | Y | Y |

IND1 | Primary inductance | Y | Y |

IND2 | Secondary inductance | Y | Y |

INDM | Mutual inductance | Y | Y |

VOLTAGE | Voltage drop between node I and node J | Y | Y |

CURRENT | Current in I-J branch | Y | Y |

CONTROL VOLT | Voltage drop between node K and node L | Y | Y |

CONTROL CURR | Current in K-L branch | Y | Y |

POWER | Power absorption | Y | Y |

For KEYOPT(1) =
9: Voltage Controlled Current Source | |||

EL | Element Number | Y | Y |

NODES | Nodes - I, J, K, L | Y | Y |

GT | Transconductance | Y | Y |

VOLTAGE | Voltage drop between node I and node J | Y | Y |

CURRENT | Current in I-J branch | Y | Y |

CONTROL VOLT | Voltage drop between node K and node L | Y | Y |

POWER | Power (loss if positive, output if negative) | Y | Y |

For KEYOPT(1) =
10: Voltage Controlled Voltage Source | |||

EL | Element Number | Y | Y |

NODES | Nodes - I, J, K, L, M | Y | Y |

AV | Voltage gain | Y | Y |

VOLTAGE | Voltage drop between node I and node J | Y | Y |

CURRENT | Current at node K | Y | Y |

CONTROL VOLT | Voltage drop between node L and node M | Y | Y |

POWER | Power (loss if positive, output if negative) | Y | Y |

For KEYOPT(1) =
11: Current Controlled Voltage Source | |||

EL | Element Number | Y | Y |

NODES | Nodes - I, J, K, L, M, N | Y | Y |

GT | Transresistance | Y | Y |

VOLTAGE | Voltage drop between node I and node J | Y | Y |

CURRENT | Current at node K | Y | Y |

CONTROL VOLT | Voltage drop between node L and node M | Y | Y |

CONTROL CURR | Current at node N | Y | Y |

POWER | Power (loss if positive, output if negative) | Y | Y |

For KEYOPT(1) = 12: Current Controlled Current Source | |||

EL | Element Number | Y | Y |

NODES | Nodes - I, J, K, L, M, N | Y | Y |

AI | Current gain | Y | Y |

VOLTAGE | Voltage drop between node I and node J | Y | Y |

CURRENT | Current at node K | Y | Y |

CONTROL VOLT | Voltage drop between node L and node M | Y | Y |

CONTROL CURR | Current at node N | Y | Y |

POWER | Power (loss if positive, output if negative) | Y | Y |

Table 124.3: CIRCU124 Item and Sequence Numbers lists output available through
the **ETABLE** command using the Sequence Number method.
See The General Postprocessor
(POST1) in the *Basic Analysis Guide* and The Item and Sequence Number Table in
this reference for more information. The following notation is used
in Table 124.3: CIRCU124 Item and Sequence Numbers:

**Name**output quantity as defined in the Table 124.2: CIRCU124 Element Output Definitions

**Item**predetermined Item label for

**ETABLE**command**E**sequence number for single-valued or constant element data

For static analyses, a capacitor circuit element is treated as an open-circuit and an inductor circuit element is treated as a short-circuit.

Only MKS units are allowed (

**EMUNIT**command).The resistor, inductor, capacitor, independent current source, and mutual inductor circuit options produce symmetric coefficient matrices while the remaining options produce unsymmetric matrices.

The sparse solver is the default for problems using the CIRCU124 element. Even if you choose a different solver, ANSYS will switch to the sparse solver when CIRCU124 elements are present.

This element may not be compatible with other elements with the VOLT degree of freedom. To be compatible, the elements must have the same reaction force (see Element Compatibility in the

*Low-Frequency Electromagnetic Analysis Guide*).