1. prof.marco

    The christmas tree circuit

    Tricky simple circuits in DC to help understand Power meaning
  2. MrsssSu

    Buffer AM signal (5W)

    Dear all, may I ask how to buffer an AM Signal so that it contains more power, maybe 5W for my Remote Control RC? I have buffered the AM signal using op-amp but the power output is just not enough. I have tried using this push-pull transistor pair, but the waveform seems to be unbuffered. I...
  3. S

    Adding Potentiometer to Fan (consumer product)

    Hello, I have a sleeping sound machine that uses a Fan to create white noise. It has a 3 position Switch, "off", "high speed", and "low speed". Essentially, these settings are either too loud or too quiet. I would like to remove the 3 setting Switch and replace it with a Potentiometer to...
  4. C

    Unusual DC power supply?

    Have you ever seen such a DC power supply as in the attachment?
  5. S

    Capacitor calculation with real and imaginary parts for a resonant converter

    Hi All, I have designed a resonant LCC converter for my thesis. It has been some time since I visited the theory and believe I used the following document by Robert Steigerwald to select the resonant components: IEEE Xplore Full-Text PDF: I was attempting to rearrange this equation for the...
  6. MrsssSu

    Linear Frequency to Linear Voltage circuit

    Dear all, the circuit above is quoted from here, and I wish to try to produce similar graph in LT Spice but I am unsure of it. The LT Spice schematic is correct since I tested it with specific 10V input AC, and it produces linear voltage on its output. However, I want to do an AC sweep on this...
  7. MrsssSu

    Reduce Frequency of Waveform

    Dear all, may I ask if there is a circuit that produces the following input and output which basically reduces its frequency by 2 times which also basically stretch out the input waveform to produce the following output? Thank you for reading :)
  8. MrsssSu

    How to freeze CD 4017 (Rain Led Chip)

    Dear all, I have successfully simulated a continuous led array that light up consecutively one after another using LT Spice and have even built one on breadboard and it works well. Well, my question is how would you freeze the led and how do we activate the clock inhibit on both the chips? Like...
  9. damador_

    TRANSFORMERS 34.5KV to 120/240V to 34.5KV to 480V

    hi! need you help I Have 3 transformes of 100KVA each 34.5Kv Primary to 120/240V in secondary I have a load of 160 KVA, 3P, 480V, so I need to get 480V in the secondary of my transformers, how can I get tthat voltage, what conextion I have to use delta-wye delta-delta PLEASE HELP ME
  10. AverageMoss

    Full-wave rectifier circuit showing half-wave rectification on oscilloscope?

    I'm new to electronics and decided to learn something new by trying to put together a small rectifier circuit that converts 24VAC to DC. So I put together a little full-wave rectifier circuit that consists of four diodes and an LED and ran into an issue when I tried to measure the DC output...
  11. M

    Need help with finding short on pcb

    I've bought a WiFi Smart Aroma Diffuser in repackaged condition, but as I've tried to use it, it didn't seem to work, as well a spark was visible when I tried to reconnect the power cable. I've disassembled it, and started testing the pcb, and I've noticed that the main power cables are shorted...
  12. T

    Using a Buck - Boost converter to get the desired output voltage

    Hi, I am using a buck boost converter MC34063 to bring 14.8 V from four Li Ion batteries in series down to three different voltages 12V, 5V and 3.3V. I am planning to use the step - down converter given in the datasheet (image below) to do this but specifically how do modify the circuits...
  13. AverageMoss

    How to detect 24VAC as 5VDC input for microcontroller?

    Hello, I'm working on a little side project for my home thermostat. I recently bought a nest smart thermostat to replace my old "dumb" thermostat and ran into an issue with the wires. I don't have enough wires to accommodate all of the thermostat functions. Running new wiring is not an option...
  14. BuyingOffDeath

    Unexplainable RF Power levels

    I have an RF Explorer to use to scan what RF's are around me. I am curious as I'm am just getting in learning about wireless transmission and propagation. However I can't explain these power levels of -10 dbm all the way to -0. The RF Explorer does seem to be working correctly just based off of...
  15. MrsssSu

    Amplify High frequency microvolts sine wave

    Dear all, I simulated a radio-receiver circuit, where I have actually build a part of the circuit which helps to amplify a sine 550kHz frequency of microvolts (antenna voltage) into several volts, however, I do not see any amplification on the output as highlighted above where I attached a...
  16. MrsssSu

    RLC resonator to produce beautiful sine wave

    Dear all, I have read about the RLC tank which can help to resonate a pulse wave of a certain frequency so that it will produce a beautiful sine wave. What would be the values of R , L and C if a 150kHz pulse square wave is used to produce a beautiful 150kHz sine wave? From what I simulated, I...
  17. MrsssSu

    AM modulation and demodulation circuit

    Dear all, above shows a modulator (transmitter) and a demodulator (receiver) and the circuit works well. However, this circuit only works if the transmitter and receiver are attached by wire. What modifications should be made to transmit the wave signal wirelessly from the transmitter to...
  18. A

    Need Help for fixing/improving boost converter design

    I'm pretty newbie. i designed a boost converter as hobby and need some help about that. not sure if it will work. how can i fix or improve the circuit. i aimed 5 Vin and 15V 10A max out and use 555 for generate pwm signal for mosfets. But i know 555 can generate max %50 duty cycle and it means i...
  19. MrsssSu

    Amplify tiny voltages accurately

    Hi all, above is a Schering's Bridge as a capacitance meter. Following the equation below, Rx resistor is fixed, whereas for capacitor Cx can be placed with an unknown value capacitor. R1 will be adjusted until voltage across R4 will be 0. The problem is that the voltage fluctuation across R4...
  20. MrsssSu

    Demodulator circuit

    Below is Triangular Modulation Output of a Triangle input wave HI all, I have been trying to understand modulation and demodulation circuitry as part of my hobby :) The modulation circuit above works fine but when I connect the output of the modulator to the demodulator (as shown by blue...