http://0.0.0.0:4000/ Table of Contents Introduction Pi Attenuator Example Calculation Calculate Ideal Shunt Element Power Dissipation Power to Voltage Calculation Calculate Branch Current Calculate Dissipated Power Implementation Tips Trace Geometry Passive Parasitics (Stray Inductance and Capacitance) Derating Preferred Resistance Values Monte Carlo Simulation What it Does Running the Simulation Analyzing the Results Summary Project Files Download Appendix A: Formulas Voltage Divider Current Divider Parallel Resistance dBm to Watts Conversion Table of Figures Table of Equations Introduction Attenuators are a fundamental building block in RF and microwave system design. Their primary function is to reduce signal power by a precise amount while presenting... Sat, 14 Mar 2026 08:00:00 +0000 http://0.0.0.0:4000/pi-attenuator-analysis/ http://0.0.0.0:4000/pi-attenuator-analysis/ Table of Contents Introduction Overview Theory of Operation Circuit Design Constant Current Charging Circuit Charging Current Transistor Circuit Design Discharge Comparator Summary Table of Figures Table of Equations Introduction Pulse Width Modulation (PWM) is a form of digital signal encoding where a unipolar, rectangular waveform’s duty cycle is varied to control the average voltage delivered to a load. The signal is characterized by a fixed frequency and amplitude, with the effective average voltage determined by the ratio of the pulse width to the total time period. This ratio is often referred to as the “duty factor”, or “duty cycle”. In... Sat, 04 Oct 2025 08:00:00 +0000 http://0.0.0.0:4000/transistor-pwm/ http://0.0.0.0:4000/transistor-pwm/ Table of Contents Introduction The Experiment Measurements Results Additional Factors Considered Conclusion Raw Data Table of Figures Introduction Have you ever wondered whether buying pistachios with shells or without shells offers the better value? For example here, there are $1360g$ of pistachios with shells offered for $\$ 16$, or $680g$ without shells for $\$18$. This article presents an experiment in which a sample from a bag of pistachios with shells was processed nut by nut, with the mass of each kernel and shell measured separately to determine not only the mass distribution of the combined sample but the ratio of... Sun, 28 Sep 2025 08:00:00 +0000 http://0.0.0.0:4000/pistachio-gravimetric-analysis/ http://0.0.0.0:4000/pistachio-gravimetric-analysis/ Table of Contents Background JFET Circuit Overview Design Example Calculation SPICE Model Usage Example Calculation Sensitivity Simulation Howland Current Source Circuit Overview Analysis Sensitivity Analysis Design Considerations Limitations Supply Limits Current Limit Resistor Trimming Thermal Management and Quiescent Power Usage Compliance Limit Additional Considerations Component Value Calculation Summary Definitions References Table of Figures Table of Equations Background Figure 1 - LTSpice Simulation Schematic Current sources are a fundamental source in electronics. They are used to generate a precise current that can be applied to a system. This system is often sensors or other measurement application where the known current is... Sun, 14 Sep 2025 08:00:00 +0000 http://0.0.0.0:4000/current-sources/ http://0.0.0.0:4000/current-sources/ Table of Contents Introduction Isolation Isolation Types Transformer (Magnetic) Isolation Capacitive RF Transmitter Optical Signal Types Voltage Loops Current Loops Operational Modes Design Optocouplers Design Overview and Operation Design Equations Bill of Materials Additional Design Considerations Simulation Simulation Files Other Applications Terms References Table of Figures Table of Equations Introduction Controllers frequently interface with analog signals for both reading and commanding parts of a system. Isolation of these signals may be desirable to protect the controller, the equipment, or decrease undesirable electrical effects (noise, ground loops, over voltage, etc). Isolating digital signals tends to be straightforward, buy a digital isolator... Sun, 06 Jul 2025 08:00:00 +0000 http://0.0.0.0:4000/optical-analog-isolator/ http://0.0.0.0:4000/optical-analog-isolator/ Introduction Dimensional Analysis of $RC$ Rise Time Calculations 10% Calculation ($t_1$) 90% Calculation ($t_2$) Solve for $RC$ Bandwidth Factor Summary Introduction Figure 1 - Bandwidth The bandwidth of a square wave depends on the rise time of the signal. That is, as the rise time of the signal decreases, the bandwidth increases. A common factor is ${0.35}/{t_{rise}}$ which is a rule of thumb approximation for the bandwidth of a signal given the $10-90\%$ risetime. The derivation and calculation of this factor is the subject of this article. First, the bandwidth of a signal refers to the spectral content of the... Sun, 18 May 2025 08:00:00 +0000 http://0.0.0.0:4000/bandwidth-equation/ http://0.0.0.0:4000/bandwidth-equation/ Table of Contents Introduction Simplified Voltage Divider Model Divider Functional Intuition (Some) Factors Affecting Design Tolerance Effects Loading Effects Thermal Effects Self-Heating Temperature Coefficient Derating Analysis Sensitivity Analysis Ratio Determination Voltage Divider Python Application Summary Introduction A voltage divider is a circuit that scales (“divides”) an input voltage. A voltage divider can be made of resistors, but can also be made from capacitors and inductors in AC circuits. Voltage dividers are lossy, passive circuits which cannot add gain to a circuit. This means that a voltage divider will never produce a voltage higher than its input. In this article the... Sat, 22 Feb 2025 08:00:00 +0000 http://0.0.0.0:4000/voltage-divider/ http://0.0.0.0:4000/voltage-divider/ Table of Contents Overview Resistance to Voltage Conversion Increasing Sensitivity with Second Element Four Element (Full Bridge) Configuration Excitation Voltage Independence PSRR and Noise Performance DC Offset and Dynamic Range Summary Overview The Wheatstone bridge is a configuration of components, typically but not always resistors, that can be used to minimize disturbances from environmental conditions. These conditions include power supply variation, noise, and component tolerances. Wheatstone bridges are used in many instrumentation systems including force (strain gauge applications), pressure, temperature, and LCR meters to name a few. In this article a mathematical analysis is performed showing the performance improvements of... Sun, 16 Feb 2025 08:00:00 +0000 http://0.0.0.0:4000/wheatstone-bridge/ http://0.0.0.0:4000/wheatstone-bridge/ Table of Contents Overview Circuit Diagram Analysis Setup Vin Component Vout Component Superposition Application - Junction Summation Switching Thresholds Shifting Threshold LTSpice Simulation Nonidealities Summary Terms Downloads Overview Schmitt triggers are a circuit building block frequently used to add a level of noise immunity to a circuit. They are used in many applications from hardware button de-bouncing, signal conditioning, to oscillator circuits to name a few. Schmitt triggers work by adding hysteresis to an input signal such that it takes an additional threshold to change states. Hysteresis is added by providing feedback from the output back to the input. Once... Sun, 29 Dec 2024 08:00:00 +0000 http://0.0.0.0:4000/schmitt-trigger/ http://0.0.0.0:4000/schmitt-trigger/ Table of Contents Overview Motivations The Connector Pinout Cable Build Option Detect Serial Interface Discovery Serial Interface Connection Cable Connection Serial Output Bill of Materials Additional Resources Overview The Ohaus Scout SPX is a portable electronic balance that has a peripheral interface connector. This connection supports many different proprietary peripherals such as printers, displays, ethernet, Bluetooth, and so on. Each of these peripherals use this same 6-position mini DIN connector. This article will discuss how this interface works and how to enable the serial port capability for just a few dollars worth of materials. Motivations This scale has been particularly... Sat, 26 Oct 2024 08:00:00 +0000 http://0.0.0.0:4000/ohaus-spx-serial-interface/ http://0.0.0.0:4000/ohaus-spx-serial-interface/ Table of Contents Introduction Static Ideal Model Model Synthesis Algebraic Steps Example Calculation Static Model Challenges Active Regulation Model Intuitive Operational Principles Detailed Analysis Efficiency Op-Amp Output Limits Gate Charge Dropout Voltage Op-Amp Slew Rate Part Tolerances and Environmental Effects Simulation Summary Simulation Files Introduction A linear voltage regulator is a device which reduces and regulates an output voltage by creating a voltage differential. There are several architectures of linear regulators such as series and shunt. This article will focus on the most common topology, the series topology. The series topology uses a series pass transistor to regulate the voltage.... Sun, 15 Sep 2024 08:00:00 +0000 http://0.0.0.0:4000/linear-voltage-regulators/ http://0.0.0.0:4000/linear-voltage-regulators/ Table of Contents Introduction Fundamental Decibel Equation Power to dB Conversion Table Example Calculations 5 Watts 1 Watt Voltage to Power Conversion Ohms Law Derivation RMS Voltage Calculation Complete Equation for Power Calculation Power from Voltage Example Time Domain Representation Code Snippet Introduction Decibels (dB) are a logarithmic unit used to express the ratio of a quantity to a reference value, enabling a more manageable representation of magnitudes spanning large ranges. Decibels are one-tenth of a Bel, a unit named after Alexander Graham Bell. The most common application of decibels is in expressing power ratios, although they can also be... Sat, 24 Aug 2024 08:00:00 +0000 http://0.0.0.0:4000/decibels/ http://0.0.0.0:4000/decibels/ Overview The Fluke 376FC is a Bluetooth wireless AC/DC clamp meter which communicates over the BLE protocol using a proprietary mobile application interface. As of writing this article there is no known desktop application or API for interfacing to this unit. Therefore the goal is to produce a working interface which connects to the unit and allows a user to interface to the device remotely from a PC. This software was developed August 2024 and was tested against: Factory new Fluke 376FC purchased from an authorized retailer Device name: 376FC Firmware version: V0.3.9 BLE Radio: 00.00.25 >>> Download ClampConnect.zip <<<... Sat, 10 Aug 2024 20:00:00 +0000 http://0.0.0.0:4000/clamp-connect/ http://0.0.0.0:4000/clamp-connect/ Overview In this article we discuss the design of a Form-A reed relay based multiplexer for test and measurement applications. Table of Contents Background Component Choices Controller Relays Connectors Shift Register Relay Drivers Implementation Layout Elements Channel Status Indication Test Points Silkscreen Firmware USB Interface Command Parser Relay logic Background Multiplexers are a highly useful device to expand the capability of existing equipment by allowing a single instrument to programmatically connect (or disconnect) upon command. Typically a multiplexer requires a mainframe and are sold individually as cards in the case of PXIe systems. They tend to be relatively expensive for... Sat, 27 Jul 2024 20:00:00 +0000 http://0.0.0.0:4000/multiplexer/ http://0.0.0.0:4000/multiplexer/ Overview In this article we discuss the design of a digital isolator with parasitically powered inputs. Table of Contents Background Features Applications and Architectures Optical Isolation Comparison Design Elements Channel Status Indication Test Points Silkscreen Component Selection Notes Resistors Connectors Custom Digital Isolators Background Digital isolators are used to keep signal return paths isolated from one another as well as protect the input to sensitive devices. They can also be used to shift logic levels such as 24V to 5V. In this project we review the implementation of a high reliability digital isolator in a miniature package. Features This system... Sun, 31 Mar 2024 09:00:00 +0000 http://0.0.0.0:4000/digital-isolator/ http://0.0.0.0:4000/digital-isolator/ Overview In this article we discuss the development of a static resistance simulator for use in functional testing. Table of Contents Background Features Fault Conditions Open and Short Circuit Faults Fault Implementation Component Selection Reed Relays Connectors Drive Circuitry Theory of Operation Architecture Input Calibration Test Open Typical Operation EEPROM LED Indication Background In test and measurement, you will often need reference standards. A reference standard in this context is a device that has a precisely known value. In other words, a known uncertainty. This can then be used as a transfer calibration standard when another device such as a... Tue, 25 Apr 2023 09:00:00 +0000 http://0.0.0.0:4000/static-rtd-simulator/ http://0.0.0.0:4000/static-rtd-simulator/ Overview In this article we discuss the statistical distribution of metal film and carbon film resistors over a 500-unit sample. Table of Contents Background Testing Procedure Results Statistical Summary Background In this experiment 1000 total resistors were purchased from an electronics supplier. Each of the resistors were produced from the same company with 500 of them being Metal Film, and another 500 being Carbon Film. These were then measured using a Keithley DMM6500 multimeter after the DMM had idled for a period of 1 hour to ensure it was up to proper operating temperature. Type Part Number Nominal Resistance Power... Sun, 30 Jan 2022 09:00:00 +0000 http://0.0.0.0:4000/resistor-tolerances/ http://0.0.0.0:4000/resistor-tolerances/ Overview In this article we discuss the modeling of a wound toroid using Solidworks. This method uses surfaces and is a very fast method of creating a helical path around a curve. This method could also be used for generating complex wrapped helix shapes around objects, too. Table of Contents Background Modeling Toroid Revolve Profile Resultant Revolve Adding Fillets Generating the Winding Create Offset Surface Create Mid-Toroid Plane Create Surface Sweep Sketch Intersection Curve Create the Wire Resulting Wound Toroid Background When you develop electronics sometimes manufacturers will not have a 3D model available. Additionally, when you deal with high-reliability... Fri, 14 Jan 2022 09:00:00 +0000 http://0.0.0.0:4000/model-wound-toroid/ http://0.0.0.0:4000/model-wound-toroid/ Overview In this article we discuss developing a custom driver, and provide source code for a 20x4 LCD targeted at the Atmel SAMD51 ARM microcontroller. While this article is targeted at the SAMD51 it is written with abstraction in mind for ease of portability between microcontrollers. Commercial use of this driver is allowed provided you attribute this article with a link and send us an email to let us know it was helpful! Table of Contents Background Hardware Software Application Interface Layer Initialization Example Middleware Layer Hardware Abstraction Layer HAL Delay Method GPIO Interface Method Source Code License Terms Header... Sat, 25 Dec 2021 09:00:00 +0000 http://0.0.0.0:4000/lcd-driver/ http://0.0.0.0:4000/lcd-driver/ Overview In this article we discuss using the Qt5 framework to create a test automation application to assist with testing of devices where hands free recording may be useful. Table of Contents Background Equipment Used Software Qt Framework GUI Organization Application Startup Testing Data Export QTableWidget Modification Example Basic Qt Editing Steps Background This system was created to fulfill a need to record continuity results while working with high density, quality critical (aerospace) application that require 100% test with retained records. The framework allows the task to utilize automation with a switch matrix and was architected in such a manner... Thu, 27 May 2021 09:00:00 +0000 http://0.0.0.0:4000/automated-continuity/ http://0.0.0.0:4000/automated-continuity/