<ammeter />

Overview

<ammeter /> measures current through a circuit branch during SPICE simulation. Insert it between the two nodes of the branch you want to measure, then connect pos and neg to define the positive current direction.

An ammeter is primarily a schematic and simulation component. It emits a current probe for simulation graphs.

export default () => (
  <board routingDisabled>
    <voltagesource name="V1" voltage="15V" schX={-3} />
    <ammeter
      name="AM1"
      color="#ff0000"
      connections={{
        pos: ".V1 > .pin1",
        neg: ".R1 > .pin1",
      }}
    />
    <resistor name="R1" resistance="10ohm" schX={3} />

    <trace from=".R1 > .pin2" to=".V1 > .pin2" />

    <analogsimulation
      duration="1ms"
      timePerStep="100us"
      spiceEngine="ngspice"
    />
  </board>
)

Pins

Pin	Aliases	Description
pin1	pos	Positive side of the current measurement.
pin2	neg	Negative side of the current measurement.

Positive current is measured entering pos and leaving neg. Reverse the connections if the plotted current has the opposite sign from the direction you want.

Properties

Property	Description	Example
name	Label for the ammeter and its current trace.	"AM1"
connections	Connects the ammeter in series. Use either pos/neg or pin1/pin2.	{{ pos: ".V1 > .pin1", neg: ".R1 > .pin1" }}
color	Color used for the current trace in simulation graphs.	"#ff0000"
graphDisplayName	Optional label for oscilloscope-style graph display.	"I_LOAD"
graphCenter	Current value shown at the center of the trace display.	0.01
graphVerticalOffset	Vertical offset from the graph center. Accepts numbers or SI-prefixed strings.	"1mA"
graphCurrentPerDiv	Current scale per division. Accepts numbers or SI-prefixed strings.	"2mA"
footprint	Optional footprint. Required if you position the ammeter on the PCB.	"0402"

Scope-style graph display

Use graphDisplayName, graphCenter, graphVerticalOffset, and graphCurrentPerDiv to override how an ammeter channel appears when an <analogsimulation /> uses graphIndependentAxes. These props are optional: without them, tscircuit automatically centers and scales the current trace from the simulated data.

graphVerticalOffset is expressed in current units, not divisions. For example, graphVerticalOffset="1mA" with graphCurrentPerDiv="2mA" places the trace center half a division away from the axis center.