1. D

    Keep running circuit while solar charging

    Hi All, I would like to build a simple automatic irrigation system with Raspberry Pi zero, the thing is that I don't have access to electricity outside. I thought to connect 5v solar panel + 3\4 chargeable batteries. Im not that familiar with building control circuits for charging batteries...
  2. Rahulk70

    A potential earth leakage or is it something else?

    Hello everyone, Hope you are all doing fine. I have been facing an electrical issue in my house since last Christmas. When the lights or any appliance with motor in any room are turned off/on the TV would go out and come back ON in a short span (as if the power went out and came back in a...
  3. markosjal

    Need help with component values for power control circuit

    I have a simple DC power control circuit that I want triggered by reed relays. It is for model railroad use. One set of reed switches detects the passing of the train . The first switch turns the power on to a trolley car so as the train passes the trolley car is moving. The second reed switch...
  4. nickhess

    Adapting an old CRT Viewfinder ( 9.3 V DC / 2.7W )

    Quarantine project: Adapting a Sony BFV-20W viewfinder Scroll down to skip the background info As a cinematographer, I've always really felt most comfortable shooting with a viewfinder. However modern electronic viewfinders all exist in the "prohibitively expensive" class of filmmaking...
  5. L

    RFID Power Delivery Wearable

    So I have a project I'm working on a project to light these "NFC fingernail lights": They light up when in the presence of a 13.56MHz RFID field. The issue is other than my phone, I have no way to light them day to day. I would like to develop a device I can hold, like fist semi closed and it...
  6. D

    Shopping advice - power supplies

    I am building my first lab and I think I will need a power supply. Was wondering if I can run my thinking through you guys and maybe ask a few questions, please! 1. Variable DC power supply - Budget: under £200. I am pretty sure I'll need this. I've already looked at some circuits that require...
  7. Marcel DaJanchar

    SMPS IC selection for automotive use: 12V to 5V

    Hello! I am working on automated pressure controller which will be used in a car. The controller consists of following: - Power supply (10V-20V input, 5Vdc 1A max output) - MCU STM32 (valve controller for pressure regulation + reading 4 pressure sensors) - WiFi functionality (ESP8266) - 8...
  8. B

    Solar emergency light/fan circuit help needed

    Hello great team! I'd immensely appreciate the help of brilliant minds out here. I've Solar rechargeable emergency unit that can power 2 lights and a small table fan. The unit stopped working with a blown resistor on the circuit. I did try replacing the resistor with an identical color coded...
  9. S

    Beginner Question - Choosing a Power Source Option for Circuit with Multiple Loads

    I'm working on designing a circuit with two distinct loads - one being a DC motor and another being an LED strip. I want to run both off the same power source, but they have different voltage requirements. The strip requires a fixed 5V and the motor will require 12V+. I'm currently planning...
  10. S

    Calculating secondary turns on transformer

    I am designing a transformer for a high voltage converter. The topology is a push-pull converter. My method is to have a 200V primary generate 4x750V secondary windings, each feeding a voltage multiplier to generate 1500V. Then connect these in series and generate the final 6kV. So far I have...
  11. Lambo Av

    Voltage Magnitude, Phases, Current for Bus (Load Flow)

    Say there are 3 buses of: Bus 1: Slack bus with a voltage source of E=1.0 and phase of 0° Bus 2: a generator and a load. Bus 3: a load. The line impedance are given below: z12 = 0.05 + j0.1 z13 = 0.02 + j0.05 z23 = j0.05 z11 = -j100 z22 = infinity z33 = -j40 The generators and loads are given...
  12. Lambo Av

    How to shut down a wind power plant?

    Just curious, how do they shut down those wind power plants given their tall structure? What are the procedures to do it? Thanks.
  13. Lambo Av

    How to shut down a hydroelectric power plant generator?

    Was cycling near a hydroelectric power plant generator with my sister and she asked me if they can be shut down. I said "Yes, all power plant generators can be shut down". I wasn't sure, so here I am to get some inputs on the safety procedures from AAC readers. Thanks. Any input is appreciated!
  14. S

    How does a power converter regulate voltage effectively at zero load current?

    I am trying to get my head around how power converters regulate the output voltage at no-load conditions. My output pulses from substantially full load ~200mA to substantially no load 0A at frequencies anywhere from 100Hz to 100kHz. My question is quite clear already but, how exactly does a...
  15. Dan Aronin

    Darlington transistor POWER AMPLIFYING

    Hi all, I just couldn't find the answer on web so I had to ask you guys. Based on my understanding, input power is ideally equal to the output power of a circuit unless it is dissipated to heat. So I was looking at the ULN2003 Darlington controlling a 28byj-48 stepper motor using an Arduino...
  16. C

    Narrowband instantaneous power

    Hey all, I got stuck on a homework question about narrowband instantaneous power. First of all, the description of the quesion: Assume a mobile traveling at a velocity of 20 km/h receives two multipath components at a carrier frequency of 1000 MHz. The first component is assumed to arrive at...
  17. S

    How to determine component values and switch dead-times in a fly-back passive snubber circuit

    I have been studying the use of snubber circuits within flyback converters and other hard-switched converters, and doing some simulations to see the results. I have came across one type of snubber called a passive snubber circuit, which uses no resistor and instead some additional passive...
  18. eliasklk_04


    Good night. I bought this flashlight for my bike: https://www.ebay.es/itm/Luces-Bicicleta-Luz-10000LM-Impermeable-3XT6-LED/292872854958?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 But the light that comes out seems very little to me. I think it has more potential. Could I modify...
  19. I

    Designing Step Up Flyback Transformer Help

    Hi. I am trying to build a power supply which output is 2000VDC and 20mA (40W) input is 220V ac (european input). I thought I can use flyback transformer. And I started to design. I selected duty cycle as %50 and frequency as 50kHz (actually I don't know how to select frequency and duty cycle...
  20. Theo_KVA

    Solar charging multiple 18650 Li-on cells with TP4056?

    Hi everyone, I plan to build a high capacity 3.7V/5V solar charging powerbank (something like 10-15ah). I’m going to use modules of TP4056 breakout board each coupled with two 18650 cells in parrallel. But I was wondering what would it need to charge two or three of these TP4056 modules with a...