Aaron Carman

Lubbock

Contributor at All About Circuits

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Articles

Capacitor Discharge: How fast in the circuit below?

4 days ago | forum.allaboutcircuits.com | Aaron Carman

By now you all should know my math skills are poor at best. I'm modifying a circuit, a "Freezer Door Open Alarm" that when the door is open C1 charges up over X time. When charged it will trigger U1A which triggers FET1 which turns on the SonAlert. The annoyance is that when loading the freezer the alarm can start to squawk. Wifey hates that. At present you have to either close the door or hold SW1 closed and wait for the cap to discharge.
Component identification

1 week ago | forum.allaboutcircuits.com | Aaron Carman

I have this trail camera, it was accidentally connected to 12v and it is only good for 6v, as you can see in the photo two components are damaged the centre one of the three is not damaged, my problem is I can’t identify the damaged parts, if any one can help me it would be greatly appreciated.
CR2032 Battery: The Tiny Powerhouse Powering Today’s Tech (2025 Update)

2 weeks ago | forum.allaboutcircuits.com | Aaron Carman

From smart devices to car keys, the CR2032 coin cell battery remains a silent hero in modern electronics. But did you know this 3V lithium powerhouse is evolving? Here's why it's still the #1 choice-and what's new in 2024. Why CR2032? Key Advantages1. Compact Size: 20mm x 3.2mm – fits anywhere2. Long Life: 5-10 year shelf life with low self-discharge3. Reliable 3V Output: Stable for digital circuits4.
Nema17 Stepper Motor Driver

2 weeks ago | forum.allaboutcircuits.com | Aaron Carman

Hi everyone,I got interested in developing Nema 17 stepper motors using ESP8266 after watching some videos on stepper motors on YouTube, which was quite interesting. My basic idea is to move an object from one end to another using strings (to hold the object in place) or similar material, these strings will be connected to stepper motors and then control these stepper motors using esp8266. Now I don't know how to choose a stepper motor driver.
Circuit or arduino?

2 weeks ago | forum.allaboutcircuits.com | Aaron Carman

Hi everyone. I have a relay NC. Sometimes, this relay will open for a few seconds and close again. In the moment it closes, I need to close a circuit for 0,5 seconds (this time is flexible, is like sending a pulse), for example with other relay. This will be done repeatedlyI don´t know how to make with analog components. I think it shoudn´t be complicated, but I have no clue.
Movellus Claims First On-Die Power Delivery Network Analyzer

2 weeks ago | allaboutcircuits.com | Aaron Carman

Movellus recently announced a new on-chip sensor that detects power transients on a nanosecond scale. The new IP provides transistor-level power delivery analytics that may improve the design and debug process at every step of fabrication.
differential amplifier

2 weeks ago | forum.allaboutcircuits.com | Aaron Carman |Jake Hertz

Hello, i saw the theory behind the differential amplifier and now im building one. VCC is 12V, VEE = -12VItail = 2mA, so ic on each resistor needs to be 1mA. What i did is first of all calculating the needed resistor in order to have 2mA on R1, so its -VEE-(-VBE)/R1=2*10^(-3) , that does R1=5.65know i know that each ic needs to be 1mA and vc needs to be at half of vcc, in order to have maximum swing, so vc is at 6Vso R2=R3 = 6k, is that correct to proceed in this way?
STM32, ESP32, ARM Cortex-M Microcontrollers: Architecture, Applications & Future Trends

3 weeks ago | forum.allaboutcircuits.com | Aaron Carman

Microcontrollers (MCUs) serve as the "electronic brains" of embedded systems, executing critical tasks from sensor data processing to real-time control. Modern MCUs like STM32 (STMicroelectronics), ESP32 (Espressif), and ARM Cortex-M series are revolutionizing industries with their integrated architectures and versatile peripherals, enabling smarter automation, IoT connectivity, and energy-efficient designs.
Voltage drop issue during load switching with AP2301B at low battery voltage

3 weeks ago | forum.allaboutcircuits.com | Aaron Carman

1I’m using two AP2301B MOSFETs in a back-to-back config to switch between battery (BATT+) and USB 5V. The gate is controlled via a 100k pull-up and 100k to GND. Attached: Oscilloscope captureSchematic Issue: When battery voltage is around 3.7V, I see a voltage dip (~2.2V drop) on VCC during switching. This resets my MCU. But when battery voltage is above 4V, the dip is gone or negligible. Questions:Why does the drop only happen at lower battery voltages?
How should I better design an Amplifier with a Comarator

3 weeks ago | forum.allaboutcircuits.com | Aaron Carman

Hello Community,I am facing a problem while building an amplifier for a Photodiode in Photovoltaic mode. I have connected a few photodiodes in series; then I applied a high-pass filter. Now I want to amplify the voltage signal across R3 (in the figure). I went with a non-inverting amplifier design with a comparator.