Floating Supply for Panel Meters Schematic Circuit Diagram

Benefits of Digital Voltmeter Modules

In today’s market, digital voltmeter modules are widely available at attractive prices. These modules offer several advantages, including exceptionally high input impedance, accuracy, versatility, compact size, and an elegant design.

Diverse Versions and Considerations

However, it’s important to note that these modules typically come in two distinct versions.

• The ‘really cheap’ which require isolation between their supply voltage and the voltage being measured.
• The ‘more expensive (expect double!) which accepts a common ground.

Isolation Circuit for Low Power Modules

When dealing with low power-consuming modules, typically around 1 mA. It’s both simple and valuable to create a circuit that provides isolation for these devices.

Circuit Description and Components

The core of the circuit is IC1, a 40106 CMOS hex Schmitt inverter. The first gate, IC1.A, functions as an oscillator with the help of R1 and C1, generating a frequency of approximately 10 kHz. IC1.B inverts this signal, allowing gates IC1.C / IC1.D and IC1.E / IC1.F to operate in antiphase. The output signal is then processed through C2 and C3, rectified using a diode bridge, filtered via C4 and C5, and stabilized to 8 V with the assistance of IC2 and C5. The input supply voltage, decoupled by C7, isn’t overly critical, falling between 10 and 15 V.

Compact Design and Application

In terms of simplicity, it’s hard to beat this circuit. The entire setup neatly fits onto a single-sided PCB measuring 24.3 × 27.94 mm, making it easy to integrate behind most display modules.

Understanding Voltmeters and Their Application

A voltmeter, also known as a voltage meter. It is an essential instrument for measuring the electric potential difference between two points in an electrical circuit. This measurement is carried out in parallel, with the voltmeter exhibiting high resistance, ensuring it draws negligible current from the circuit.

Practical Example

For instance, if you wish to measure the voltage across the terminals of a fully charged car battery. The voltmeter will display a reading of 12.6 Volts DC. This indicates a potential difference of 12.6 volts between the battery’s positive and negative terminals.