Current Source
Current source with optional DC, AC and noise components.
Description
The Current Source block is a current source with DC, AC, and noise components. The current flowing through the source from terminal - to terminal + is determined as follows:
,
where:
-
- DC component.
-
- amplitude of the AC component.
-
- frequency of the alternating current component.
-
- phase shift of the AC component.
-
- noise current.
You can configure the Current Source block as a DC only source, AC only source, or a combination of both. By default, both AC and DC components are 0. Define AC/DC by specifying non-zero parameter values after placing the block in the model.
The noise component is also optional. If you select the check box for Noise mode, the added noise current will be defined as follows:
,
where:
-
- is the power spectral density of one-way noise for a 1 ohm load, in .
-
- is a random number with zero mean and unit standard deviation.
-
- period of generation of noise values.
By default, the Noise mode checkbox is unchecked and the current source does not generate thermal noise.
Noise parameters
The unit generates noise according to a normal distribution using a random number generator. You can influence the random number generation by adjusting the Repeatability parameter:
-
Not repeatable- every time you simulate the model, the block will re-generate a seed using the random number generator.
-
Specify seed- when this option is selected, the optional Seed parameter allows you to specify the seed directly.
Parameters
DC & AC Components
DC current - output DC current
`0 (By default)
Output DC current. Specify a non-zero value to add a DC component to the current source.
AC current peak amplitude - AC current peak amplitude
`0 (By default)
The amplitude of the output AC current. Specify a non-zero value to add an AC component to the current source.
AC current phase shift - AC current phase shift
`0 (By default)
AC current phase shift.
AC current frequency - AC current frequency
50 Hz (By default).
The frequency of the AC output current.
Noise
Enable noise mode - Noise enabled
off (By default) | on
Select the check box to enable noise.
Dependencies
Selecting the Enable noise mode check box opens the related parameters.
Power spectral density - power spectral density
`0 (By default)
One-way noise power spectral density. Density function for the square of the current, usually considered as the power in a 1 ohm load. To avoid ambiguity in units of measurement, some specifications define noise current as noise density in units of A/√Hz. In this case, enter the square of the noise density specified in the specification as the parameter value.
Dependencies
To use this parameter, select the Enable noise mode checkbox.
Repeatability - random number sampling control
Not repeatable (By default)` | Specify seed.
To control the generation of random numbers, set this parameter to the following value:
-
Not repeatable- the seed of the random generator changes every time you simulate the model. -
Specify seed- allows you to specify an explicit seed value using the Seed parameter.
Dependencies
To use this parameter, select the Enable noise mode checkbox.
Seed - seed of random number generation
0 (By default)
Seed used by the pseudorandom number generator. The initial value must be 0 or a positive integer.
Dependencies
To use this parameter, select the Enable noise mode checkbox and the Specify seed value for the Repeatability parameter.
Sample time - period of generation of noise values
1e-3 s (By default).
Defines the frequency of random number generation for the noise source. Set this value to reflect the frequencies of interest in your model. Too small an interval between calculation steps will slow down the simulation unnecessarily.
Dependencies
To use this parameter, select the Enable noise mode checkbox.