CCVS (Dependent Voltage Source) Symbol
Definition: The CCVS symbol represents a current-controlled voltage source — a dependent source whose output voltage equals a transresistance rm (in ohms, volts per amp) times a controlling current flowing through a designated branch elsewhere in the circuit — drawn per IEEE 315 / ANSI convention as a DIAMOND containing + and − marks, with the controlling branch (Ctrl In, Ctrl Out) carrying the sensed current.
Also known as: current-controlled voltage source, dependent voltage source, controlled voltage source, H source, transresistance source, transimpedance source, rm source.
What the CCVS (Dependent Voltage Source) symbol means
The CCVS symbol denotes an idealized two-port element in which a controlling branch (Ctrl In to Ctrl Out) carries a current ix — ideally through zero resistance, so sensing it disturbs nothing — and an output port (+, −) imposes a voltage vout = rm·ix on the rest of the circuit regardless of load current. The gain rm is a transresistance (also called transimpedance), measured in ohms, because it converts an input current into an output voltage: volts out per amp in.
The CCVS is the idealization behind every transimpedance amplifier — the circuit that turns a photodiode's microamps into a usable voltage — and appears in two-port network theory as the h-parameter and z-parameter forward-transfer elements. In SPICE it is the H element, and because SPICE can only sense current through a voltage source, the controlling current must flow through a named voltage source (often a 0 V dummy source acting as an ammeter): H1 out+ out− Vsense rm.
How to identify the CCVS (Dependent Voltage Source) symbol
The output side is a DIAMOND containing + and − signs: a dependent source (diamond) that produces a voltage (±). What makes it current-controlled rather than voltage-controlled is the controlling quantity: instead of a high-impedance voltage-sensing pair, the schematic shows a series branch — Ctrl In and Ctrl Out terminals, often drawn as a short loop or a labeled wire on the left — through which the controlling current ix flows, with the gain annotated as rm·ix beside the diamond.
Compare the four siblings: diamond-with-± controlled by a current is the CCVS (H); diamond-with-± controlled by a voltage is the VCVS (E); diamond-with-arrow controlled by a current is the CCCS (F); diamond-with-arrow controlled by a voltage is the VCCS (G). On IEC-style schematics the diamond may be replaced by an annotated circle, so read the gain expression — an ix inside it means current-controlled.
Live editor identity: Live-library identity: `ccvs`, 60 × 60 canvas units, 4 logical terminals. Match this exact SVG and terminal list when identifying the placeable editor symbol; do not identify a physical package from the schematic outline alone.
Function and usage boundary
In analysis, the CCVS enforces vout = rm·ix, where ix must be identified as the current through a specific branch. This couples mesh equations naturally (the controlling current is often a mesh current), while in nodal analysis the controlling branch typically needs an auxiliary equation. The controlling branch is ideally a short circuit — zero volts dropped while sensing — and the output is an ideal voltage source with zero output impedance.
Practically the CCVS models current-to-voltage conversion. A transimpedance amplifier (op-amp with feedback resistor Rf on a current input) realizes vout = −Rf·iin, a CCVS of transresistance Rf. Current-shunt monitoring — a shunt resistor plus amplifier producing a voltage proportional to load current — is CCVS behavior at system level, and the forward voltage transfer in h-parameter BJT models (hre term aside) and z-parameter two-ports is written with CCVS elements.
Usage boundary: Use the CCVS (Dependent Voltage Source) abstraction only when the intended circuit can be expressed through these logical ports: `pos` (+), `neg` (-), `ci` (Ctrl In), `co` (Ctrl Out). Select a versioned physical profile and exact manufacturer datasheet before assigning package pins, ratings, or fabrication dimensions.
Standards: IEC vs ANSI
| IEC 60617 | IEC 60617 defines no separate diamond for controlled sources; IEC-tradition schematics annotate a source circle with the controlling law (rm·ix). The diamond convention is nonetheless standard in international textbooks and simulation documentation. |
|---|---|
| ANSI/IEEE 315 | IEEE 315 / ANSI practice draws the CCVS as a diamond with internal ±, the controlling current identified on a designated branch. SPICE implements it as the H element, sensing the controlling current through a named voltage source: H<name> out+ out− Vsense gain. |
| Key difference | Diamond (IEEE/textbook, dependent) versus annotated circle (strict IEC) is the visual split, identical to the other dependent sources. Unique to the current-controlled pair (H and F) is the SPICE requirement that the controlling current flow through a voltage source — commonly a 0 V dummy source inserted as an ammeter — since SPICE cannot reference a branch current directly by node names. |
The displayed SVG is the live editor implementation, not a licensed reproduction or certification of an IEC or IEEE database glyph. Verify the exact official entry and project edition before issuing work.
Variant availability
- Editor implementation (available): This is the exact SVG and terminal geometry placed by the CircuitDiagramMaker editor.
- IEC 60617 (reference only): IEC 60617 is the official international source. This page does not present the editor SVG as a licensed or certified IEC reproduction.
- ANSI/IEEE 315 (reference only): IEEE 315 is the North American reference listed by IEEE as inactive-reserved; use the edition required by the project.
Logical terminals
The live editor exposes `pos` (+), `neg` (-), `ci` (Ctrl In), `co` (Ctrl Out). These are stable logical terminal IDs for diagram connectivity, not a promise that they equal physical package pin numbers.
| Logical ID | Editor terminal name |
|---|---|
| pos | + |
| neg | - |
| ci | Ctrl In |
| co | Ctrl Out |
Polarity and direction
Polarity or supply meaning is encoded on `pos` = +, `neg` = -. Do not reverse these logical connections, and verify the physical package pin number in the exact device datasheet.
Reference designator
Project-defined: No single reference letter is asserted for this broad symbol. Apply the project standard and equipment-classification rules consistently.
Where the CCVS (Dependent Voltage Source) symbol is used
- Transimpedance amplifier models converting photodiode, PMT, or DAC output currents into voltages
- Current-shunt monitoring circuits that report a voltage proportional to a measured load current
- Two-port network theory: forward transfer elements of z-parameter and hybrid-parameter equivalent circuits
- SPICE behavioral modeling where a branch current must set a node voltage (H element with a 0 V sense source)
- Hall-effect and current-transformer measurement chains modeled at system level as volts-per-amp blocks
- Textbook dependent-source exercises in mesh analysis, where the controlling variable is a mesh current
Key facts
- The CCVS equation is vout = rm·ix; rm is transresistance (transimpedance) in ohms — volts of output per amp of controlling current.
- Symbol: diamond (dependent) with ± inside (voltage output); the controlling current flows through a designated series branch (Ctrl In / Ctrl Out).
- SPICE letter H denotes the CCVS; the controlling current must pass through a named voltage source, e.g. H1 out+ out− Vsense 1k.
- A 0 V dummy voltage source is the standard SPICE trick for sensing the controlling current without disturbing the circuit.
- The ideal CCVS drops zero volts across its sensing branch (perfect ammeter) and has zero output impedance (perfect voltage source).
- The transimpedance amplifier — op-amp with feedback resistor converting input current to output voltage — is the everyday physical realization of a CCVS.
- Among the four dependent sources it is the least common in device models but central to current-measurement and two-port z-parameter representations.
- Like all dependent sources it stays active during Thevenin/Norton analysis; only independent sources are zeroed.
Common interpretation mistakes
- Treating the CCVS (Dependent Voltage Source) drawing (60 × 60 canvas units) as a physical footprint. The schematic outline expresses electrical intent; package and panel dimensions come from the selected physical profile.
- Copying `pos`, `neg`, `ci`, `co` directly to a wire marker or manufacturer package pin number. These are logical CCVS (Dependent Voltage Source) port IDs and require an exact ordered-part terminal map.
- Reversing a polarity-marked CCVS (Dependent Voltage Source) terminal because the symbol was rotated or mirrored on the sheet.
Frequently asked questions
What is the difference between a CCVS and a VCVS?
Both output a voltage (diamond with ± inside), but the controlling variable differs. A VCVS senses a VOLTAGE vx across two nodes with an open-circuit control port and outputs μ·vx (gain dimensionless, V/V). A CCVS senses a CURRENT ix flowing through a branch — ideally with zero voltage drop — and outputs rm·ix (gain in ohms, V/A). Check the gain expression: vx means VCVS, ix means CCVS.
Why are CCVS gain units ohms?
Because the gain converts amps into volts: rm = vout/ix has units V/A, which is the ohm. The quantity is called transresistance or transimpedance — 'trans' because the current and the voltage are at different ports, unlike an ordinary resistor where V and I share one branch. A transimpedance amplifier with a 1 MΩ feedback resistor is a CCVS of one million ohms: 1 µA in gives 1 V out.
How do I write a CCVS in SPICE?
Use the H element, and route the controlling current through a voltage source so SPICE can measure it. If no real voltage source exists in that branch, insert a 0 V dummy: Vsense a b 0 followed by H1 out+ out− Vsense 1k creates vout = 1000 × I(Vsense). The zero-volt source behaves as an ideal ammeter and does not alter circuit operation. E/G/H/F is the full dependent-source letter set — H is specifically the CCVS.
What real circuit does a CCVS model?
The transimpedance (current-to-voltage) amplifier is the canonical example: an op-amp with a feedback resistor Rf converts an input current from a photodiode or DAC into vout = −Rf·iin. Current-shunt monitors, current-transformer burden circuits, and Hall-sensor chains are also volts-per-amp blocks. In network theory, the forward-transfer branches of z-parameter and h-parameter two-port models are written as CCVS elements.
How is the controlling current shown on a CCVS schematic symbol?
As a designated branch — often a short loop or wire segment labeled with the current ix on the control side of the symbol (the Ctrl In and Ctrl Out terminals) — rather than the +/− sensing pair used by voltage-controlled sources. The diamond's value annotation (e.g. '50·ix') names that current. In textbook problems the controlling branch is frequently elsewhere in the circuit entirely, identified only by the ix label on some element's wire.
Sources and verification
- IEC 60617:2026 DB — Graphical symbols for diagrams (International Electrotechnical Commission) — The current official IEC graphical-symbol database and the electrotechnical areas it covers. Exact symbol identity data requires IEC access.; claim scope: standards
- IEEE/ANSI 315-1975 — Graphic Symbols for Electrical and Electronics Diagrams (IEEE Standards Association) — The official catalogue record for North American diagram symbols and reference-designation letters; IEEE lists the standard as inactive-reserved.; claim scope: standards, reference_designator
- IEC 61666:2010+AMD1:2021 — Identification of terminals within a system (International Electrotechnical Commission) — General principles for identifying terminals within systems; it does not replace the exact ordered-device datasheet.
- IEC 81346-2:2019 — Object classes and reference-designation codes (International Electrotechnical Commission) — The official classification scheme used to form reference designations across technical disciplines.; claim scope: reference_designator
- IEC 61082-1:2014 — Preparation of documents used in electrotechnology (International Electrotechnical Commission) — General presentation rules for electrotechnical diagrams, drawings, and tables.; claim scope: standards, usage
Geometry fingerprint: 505e39ca64b2331a. A changed SVG, canvas size, or terminal definition invalidates the recorded review.
Related symbols
- Amplifier Block symbol
- Current Source symbol
- Current Transformer (CT) symbol
- Op-Amp symbol
- Transimpedance Amplifier symbol
- Voltage Source (DC) symbol
Physical breadboard, PCB, and panel mapping
No universal physical profile is published for this symbol yet. Create a versioned custom part from the exact manufacturer dimensions and terminal map before fabrication.
Place the CCVS (Dependent Voltage Source) symbol directly on a wiring diagram or schematic in the free online editor — no download required.