• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.


  1. J


    - At a given KV rating, will a motor with higher Watts have more torque? - At a given watts rating, will a motor with lower KV's have more torque? - Can we calculate KV from rpm and volts? Eg, 4900rpm/72V=68KV ?
  2. 1

    Motor Speed Controller

    Hello, I have an 125 mm angle grinder with 720 W AC motor and soft start (attached pdf document). I want to build a speed controller for this angle grinder. I tested a simple triac dimmer (from the attached jpg schematic) but it doesn't work normally, because it is making a strange buzzing...
  3. 1

    Arduino ON led lights up with no USB, no Vin and no 5V power

    Hello, I am using an Arduino Uno for a soldering station project. I am powering the Arduino through USB port using a L7805 regulator and I saw that if I remove the USB power, the ON led still lights up when I am powering the soldering station. Also, the other led's are semi light up. The Vin and...
  4. Q

    Troubleshooting an old tablet that has power supply issues

    Hi, I'm quite "new" to the world of electronics I have a CS background and I have a quite old tablet laying around that has power supply issues... it started randomly turning off so I used it with the charger plugged in for a while and now it doesn't turn on. I managed to start disassembling and...
  5. M

    DC 120V converter circuit

    I have many strings of LED Christmas lights, but they flicker on 120 VAC. If I could feed them 120 VDC, that would solve the problem. Simple bridge/filter circuits produce 170 VDC, wchi will burn out the lights pretty quickly. I've come across a few circuits that seemed unnecessarily complex...
  6. I

    Help locating male power plug component

    I'm working on a small electronic device (rf remote receiver to home automation system bridge) that I would like to package into a small box that plugs directly into the wall. I am, however, having some difficulty locating the "plug" component. I can find plenty of sockets into which I can plug...
  7. A

    3 phase 3 wire measurement

    Dear all, I am trying to build 3 phase voltmeter that could measure L-L and L-N voltage during 3 phase 3 wire and 3 phase 4 wire connection. 3 phase 3 wire and 3 phase 4 wire connection are external connection. as we know in 3 phase 4 wire we will get neutral reference so we can get...
  8. W

    Bluetooth door opener, Choose a stepper motor or a servo motor?

    Hello everyone, I need the help of the Community, I am working on a project, I need to create a device that can open or close a door lock via Bluetooth, this device works on batteries and it is just a simple adapter that you plug on your existing door lock, you just put the key Inside and it...
  9. S

    Need help designing a 194.0 °F bioreactor for cell culture.

    I've been having trouble deciding how to design a 194.0 °F (90ºC) bioreactor for cell culture (not cell culture now but I do need to get to that temperature to take a sample). Its supposed to be an incubator, basically a 3mm thick 5.5"x5.5"(14 cm) acrylic box, but I'm not sure If I can reach...
  10. Rayhan

    How to fix ventmed ds7 bipap power problem ??

    After powering theke display lightsup but power button has no light and power. Please any body help me to fix it.
  11. D

    unregulated power supply - unstable output or no output at all

    This might be a super obvious question to most over here, but I know nothing about power supplies, so please bear with as I try to explain what is going on. I have one of these SPS705 68VDC power supplies running inside a rather simple stepper motor control box...
  12. Clarkdale44

    Relay timer 2 min on and 10 min off, and repeat constantly.

    Hello I want to make an auto relay timer circuit such that it turns on the load connected to the relay for 2 min then turns off for 10 min and repeats this cycle indefinitely. I have a few 555 timer lying around was hoping if could make something out of it. The timings doesn't needs to be...
  13. mading2018

    Measure temperature and power losses?

    I know that it is possible to measure the power dissipation in LTspice according to this source: "To measure the wattage dissipation of a component , place the cursor on the components and press and hold down the ALT key, a thermometer cursor should appear. Read the Watts on the bottom screen...
  14. O

    need help badly with a forward converter

    I need help with the design of a 12v-24v forward converter, i need to be shown the maths for working out the output inductor and capacitor values and the turns ratio of the transformer (which i think ive worked out) please help. dissertation work
  15. DGM

    Details of the simulated dissipation constant in thermistor spice model

    I'm working on a project involving the simulation of NTC thermistors both in LTSpice and my own optimization scripts in Matlab. In the process of debugging, I noticed that LTSpice was producing unexpected behavior for a circuit I'd put together. The circuit in question is a thermal anemometer...
  16. N

    Are there any generators that produce little or no counter torque?

    Maybe a silly question, I understand that when an electrical load is placed on a generator, the generator produces a counter torque, thus requiring more power to maintain the rpm. I was just wondering are there any electrical generator designs that produce little or even no counter torque, or...
  17. L

    How can I connect my circuit to power?

    I am trying to build an escape room puzzle, where someone holds a key fob up to a sensor and a maglock opens, and I went online to buy something that I assumed was ready-in-box but instead they sent me the photo attached which I'm 99% sure was originally a car immobilizer and is now being used...
  18. sr13579

    Is it safe to use a 5V-1A USB(Samsung mobile) charger for lm386?

    Hello everyone, A brother from my hometown told me to make a mini amplifier that can pull the power out from a USB charger(or PC USB). I happened to working on a logic gate IC and burned the IC while using a USB(power bank) charger. I want to know is it safe to use a 5V-1A charger to power the...
  19. A

    Sourcing surface mount high current connector

    Hi All I'm having a dilemna at the moment, I have designned a battery balancing circuit and need connector for this that are rated at 10A max per contact perivously I used a SAMTEC IPBT connector which met my requirement the only problem was the height with the connector and the mating half had...
  20. A

    Simulating IGBT in LTSpice

    Hi all Can anyone help me to simulate an IGBT in LTSpice I am trying to create a model for the IGBT in the datasheet attached I am not 100% how I go about doing this in LTspice I know that in the new version of LTSpice there are nIGBT's but I am not sure which parameters I need to add to this...
  21. P

    switched power supplies for beginners

    Hello everyone I want to start studying switched power supplies and ask for help to indicate which is the best book on this subject for anyone who is starting out. Thank you all for helping me.
  22. Singul4rity

    LG 29inches ultrawide, not enough power?

    I bought recently a brand new LG 29UM58 IPS 29 inches ultrawide from amazon. When I recieved it, I notice that came with a 110v power adapter so I bought a 7 bucks converter 220v to 110... the monitor started, and shows gray screen saying "No input connected" when I connected the HDMI cable, the...
  23. I

    50 Hz oscillator based on a LM324N IC

    hello everyone I want to build a 50 Hz oscillator circuit using the LM324N IC, any body have a schematics to how and what components I'm gonna need ? thanks
  24. Matienzo

    Heated 35x50 mm surface.

    Hi there, I'm trying to create an electric heater for an insect repellent mat. The only constraint is that I must use a 18650 battery. The mats are about 35x50 mm and they need to be heated at about 130F. In the chat, Mike_2545 suggested a power resistor like this one and also pointed...
  25. N

    Would a high voltage low current generator be more efficient?

    Generators have to deal with counter torque. The more electrical load placed on the generator, the greater the counter torque. Since the counter torque is a function of load current, if one designed a generator to be low current/high voltage, and in conjunction used a transformer to then convert...

Latest threads

EE World Online Articles