Supported mathematical functions, operators and constants
Mathematical functions:
| Function name | Alternate name | Parameters | Description | Notes |
|---|---|---|---|---|
| if | — | <code>(test,a,b)</code> | If-else function. If the test returns true, the result is a, else it returns b. |
Example: B1 out 0 V={if(v(1)>5, v(1)**2, 0)} |
| sin | sine | <code>( x )</code | Sine function. | — |
| asin | arcsin | <code>( x )</code | Arc-sine function. | — |
| sinh | — | <code>( x )</code | Hyperbolic sine function. | — |
| asinh | arcsinh | <code>( x )</code | Arc-hyperbolic sine function. | — |
| cos | — | <code>( x )</code | Cosine function. | — |
| acos | arccos | <code>( x )</code | Arc-cosine function. | — |
| cosh | — | <code>( x )</code | Hyperbolic cosine function. | — |
| acosh | arccosh | <code>( x )</code | Arc-hyperbolic cosine function. | — |
| tan | — | <code>( x )</code | Tangent function. | — |
| tanh | — | <code>( x )</code | Hyperbolic tangent function. | — |
| atan | arctan | <code>( x )</code | Arc-tangent function. | — |
| atanh | arctanh | <code>( x )</code | Arc-hyperbolic tangent function. | — |
| atan2 | — | <code>( x, y )</code. | Atan 2 function. | Same as: <br>atan (x/y) |
| exp | — | <code>( x )</code | Calculates the exponential e<sup>x</sup>. | — |
| expl | — | <code>( x )</code | Calculates the exponential with a maximum value. | Same as: <br> min (exp (x), y) |
| ln | — | <code>( x )</code | The natural logarithm function. | — |
| log10 | — | <code>( x )</code | The base-10 logarithm function. | — |
| log | — | <code>( x )</code |
The generic logarithm function. This function is included for legacy compatibility and its use is not recommended. |
Normally this is the same as ln(x) except in 'B' arbitrary sources where it is log10(x). This behavior is also changed by the .SYNTAX statements. |
| sqrt | — | <code>( x )</code | Square root function. | — |
| abs | — | <code>( x )</code | Absolute value function. | — |
| sgn | — | <code>( x )</code | Sign or signum function. |
if (x < 0) sgn(x) == -1 if (x > 0) sgn(x) == 1 if (x == 0) sgn(x) == 0 |
| max | — | <code>( x, y )</code. | Returns the maximum of x and y. | — |
| min | — | <code>( x, y )</code. | Returns the minimum of x and y. | — |
| uramp | — | <code>( x )</code | Ramp function, clips the value against a minimum of 0. |
if (x < 0) uramp(x) == 0 if (x >= 0) uramp = x |
| u | stp, step | <code>( x )</code | Step function. |
if (x < 0) u(x) == 0 if (x > 0) u(x) == 1 if (x == 0) u(x) == 0.5 |
| table | — | <code>(expr, x1,y1, <x2,y2 <...>>)</code> |
Piecewise linear function. Specified x-values must be increasing in value from left to right. Inputs below x1 result in an output equal to y1. Inputs above xn (the largest specified x-value), result in an output equal to yn. In other words, table function acts as a limiter in those regions. Using this function in a Value-type Arbitrary source is functionally equivalent to using the Table-type source. |
The following line: E1 out 0 value={Table(v(in), -60m,-4,0,0,140m,43.3)} is functionally equivalent to the following line: E1 out 0 TABLE {v(in)} (-60m,-4,0,0,140m,43.3) |
| limit | — | <code>( x, a, b ) </code> | Clips the input value x to the range (A,B). | — |
| pwr | — | <code>( x, y )</code. | The pwr function. |
Same as: abs(x)^y |
| pwrs | — | <code>( x, y )</code. | The pwrs function. |
if (x < 0) pwrs(x) == -(x**y) if (x >= 0) pwrs(x) == (x**y) |
| ddt | — | <code>( x )</code. | Time derivative. | ddt(v(1)*v(CapVoltagenode)) |
| sdt | — | <code>( x )</code. | Time integral. | 1meg*sdt(I(Vsense)+8) |
| V | — | <code>(node)</code> | Voltage of a node. | Can only be used in non-linear controlled source expressions. |
| V | — | <code>(node1, node2)</code> | Voltage difference of two nodes. |
Can only be used in non-linear controlled source expressions. Same as: V(node1)-V(node2) Example: E1 out 0 value={V(1,2)*15} |
| I | — | <code>(voltage source) or (inductor)</code> | Current through a voltage source or an inductor. |
Can only be used in non-linear controlled source expressions. Example: E1 out 0 value={I(Vsense)**2 + I(E99)}<br>Vsense and E99 are the SPICE netlist names of the devices. They are case insensitive. |
| positive | — | <code>( x )</code | Ensure positive function. |
if (x < d) positive(x) = d else positive(x) = x where d is 1.0p |
| negative | — | <code>( x )</code | Ensure negative function. |
if (x > -d) negative(x) = -d else negative(x) = x where d is 1.0p |
| nonpos | — | <code>( x )</code | Ensure not-positive function. |
if (x > 0) nonpos(x) = 0 else nonpos(x) = x |
| nonneg | — | <code>( x )</code | Ensure not-negative function. |
if (x < 0) nonneg(x) = 0 else nonneg(x) = x |
| nonzero | — | <code>( x )</code | Ensure non-zero function. |
if (x < d) & (x >= 0) nonzero(x) = d if (x > -d) & (x <= 0) nonzero(x) = -d else nonzero(x) = x where d is 1.0p |
| zero | — | <code>( x )</code | Evaluates x but always returns a value of 0.0. | — |
| one | — | <code>( x )</code | Evaluates x but always returns a value of 1.0. | — |
| schedule | — | <code>(x1,y1, <x2,y2<…>>) </code> | Schedule function. Gives a value of yN for when time between xN and xN+1. | Time is simulation time. |
Mathematical operators:
| Symbol | Alternate Symbol | Description | Usage |
|---|---|---|---|
| + | Addition. | A + B | |
| - | Subtraction. | A - B | |
| / | Division. | A / B | |
| * | Multiplication. | A * B | |
| ** | ^ | Exponentiation (power). |
A ** B or A ^ B These take the absolute value of the base. This is consistent with PSpice®. This can be interpreted differently in other simulators. |
| < | Less than. | A < B | |
| <= | Less than or equal to. | A <= B | |
| > | Greater than. | A > B | |
| >= | Greater than or equal to. | A >= B | |
| == | Equal to. | A == B | |
| != | Not equal to. | A != B | |
| & | Logical AND. | A & B | |
| | | Logical OR. | A | B | |
| xor | Logical XOR. | A XOR B | |
| ?: | Ternary if. This operator has two symbols and three operands. |
A ? B : C This is the same as IF(A,B,C). |
Built-in constants
| Symbol | Description | Value |
|---|---|---|
| true | Boolean true value. | 1.0 |
| false | Boolean false value. | 0.0 |
| yes | Alternate form of boolean true value. | 1.0 |
| no | Alternate form of boolean false value. | 0.0 |
| pi | The constant pi. | 3.14159265358979323846 |
| e | The constant e. | 2.71828182844590452353 |
| c | The speed of light. | 2.99792458e8 |
| kelvin | Constant to convert between degrees Kelvin and Celsius, and vice versa. | -273.0 |
| echarge | Electron charge. | 1.602176487e-19 |
| boltz | Boltzmann's constant. | 1.3806503e-23 |
| planck | Planck's constant. | 6.62606896e-34 |
| temp | Current temperature of the simulation in degrees Celsius. | The default is 27, but it can be changed from the simulation options. |
| time | Current time of the simulation in seconds. | Current time of the simulation in seconds (it is constant with respect to circuit variables). |
IMPORTANT! Unlike most mathematical languages, Multisim considers the unary minus to have higher precedence than exponentiation (power) operators ** and ^. This means that {-5**2} is +25 while {0-5**2} is -25. Although this is unintuitive, it is standard among SPICE simulators. Use brackets to ensure logical, readable expressions in this case.
