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Tracking Voltage and Current in Electric Circuits

Published Date
Author Cadence PCB Solutions

Key Takeaways

  • In any electrical circuit, it is necessary to track voltages and currents to ensure proper operation.

  • Depending on the circuit application platforms, the level of accuracy required, and the precision expected in readings, the methods to track voltage and current vary.

  • The circuit performance can be improved by optimizing the circuit design after analyzing the voltage and current. 

Tracking voltage and current

In any electric circuit, it is necessary to track the voltages and currents to ensure proper operation

If an electrical circuit is functioning, then there is a flow of electric charge or current in the circuit. For the current to flow between two points, a potential difference is essential. The characteristics of a circuit can be evaluated from the voltages and currents.

In any electric circuit, it is necessary to track the voltage and current to ensure proper operation. There are a few different methods to accomplish this: digital multimeters, voltmeters, ammeters, voltage sensors, current sensors, oscilloscopes, data loggers, etc. 

Why Bother Tracking Voltage and Current?

Tracking voltage and current is advantageous for a few reasons:

Failure-Free Operation

Tracking the voltages and currents in an electrical circuit is important to ensure the safe operation of components. Active and passive components are selected by considering the electrical and thermal aspects of the electrical design. The electrical quantities that are commonly considered in any component selection are the voltage and current rating. Besides the tolerance provided, there will be a safe limit up to which one can increase the voltage or current through the component. 

Avoiding Open and Short Circuits

By tracking down the voltage and current, the potential issues of short circuits and open circuits can be identified. For example, excessive current flow through a wire can be taken as a hint of a short circuit or a component failure. Similarly, if a switch gets opened while in operation, the current drops to zero, and monitoring of the switch current indicates an open circuit. In this way, the tracking and monitoring of the circuit voltages and currents help in keeping the circuit operating as intended.

Optimization

Optimizing the performance of the circuit is possible by adjusting the system parameters. Take for example the continuous and discontinuous operation of power electronic converters. By varying the inductor value, the required mode can be obtained, and this is realized by measuring the current. By continuously monitoring the various voltages and currents in a circuit, design can be optimized. Performance parameters such as output voltage quality and power efficiency can be improved in this way.

How Do You Track Voltage and Current?

Depending on the circuit application platforms, the level of accuracy required, and the precision expected in reading, the methods for tracking voltage and current vary. Methods include digital multimeters, digital storage oscilloscopes, and current or voltage sensors. Direct measurement using voltmeters and ammeters is the oldest method used.

In digital multimeters, analog-to-digital conversion is utilized to display the voltage or current measurement. In an oscilloscope, the voltage and current probes are used to measure the voltage and current, respectively. The waveforms can be viewed on the display screen and the same can be stored on memory cards or flash drives in new-age oscilloscope models.

Some other voltage and current tracking methods are listed below.

Resistive Potential Dividers 

Resistance potential dividers are used to reduce the voltage at a point in the circuit. The voltage range of measurement is lowered so that it can be measured using voltmeters or multimeters.

Current Shunts

In current shunts, a resistor is connected to the circuit, which gives a voltage proportional to the current to be measured. This voltage measurement can be performed using any direct method.

Rogowski Coils

A Rogowski coil is a type of current sensor that uses a wire loop to produce a voltage proportional to the current flowing through the circuit. Inserting the Rogowski coil into the wire where you want to measure the current produces equivalent voltage, and using the proportionality calculation, the current can be calculated from the voltage measurement.

Tracking Voltage and Current in SPICE Models

Circuit performance can be analyzed and optimized after analyzing the voltages and currents from a SPICE simulation. Potential problems of overloading, component failure, power supply issues, etc. can be identified from SPICE models. Solving these issues before moving to hardware saves time and money.

Tracking voltages and currents in a SPICE model gives the designer an in-depth understanding of circuit behavior. SPICE simulation can be considered a verification check on the circuit performance.

Cadence offers SPICE simulation tools where the designer can get a 360-degree experience of the circuit behavior at different temperatures, loading, and frequency conditions. Leading electronics providers rely on Cadence products to optimize power, space, and energy needs for a wide variety of market applications. If you want to learn more about our innovative solutions, talk to our team of experts or subscribe to our YouTube channel.