1. vouzmevoyez

    Unable to get lower duty cycle for monostable w/ astable input via opamps

    Hi, I have to keep my frequency ~800Hz which means T = 1.25ms. Using a variable resistor, I have to get a duty cycle of 65% (which I achieved @ Rpot = 23.5k ohms) and 15% when the potentiometer is at 0. However when I try to trial and error simulation values, my output waveform doubles per...
  2. G

    Zener Diodes in series as Voltage Regulators

    I’m attempting to confirm my approach to this project circuit. I’m wondering if the 2 halves of the circuit (as shown) would work well to drive the Load, or even work together well at all. (It’s been a while since I was designing circuits (30+ years) and I’m a bit rusty.) I’ve done a...
  3. jkelly662

    Amplifier Crowbar Circuit Help

    Hi, I've reverse engineered the crowbar circuit on a large amplifier I'm working on. I understand the basics of how a crowbar is supposed to work, but this particular design is difficult for me to grasp. The input voltage is +/-250 VDC. The K1 relay appears to disable the crowbar when the relay...
  4. Rahulk70

    Recapping and FM tuner station issue on Technics SA-5360 Stereo FM/AM tuner amplifier

    Hello everyone, I had recently purchased a Technics SA-5360 Stereo amp tuner from eBay. This was after a long break since 2019 I took from my vintage electronics hobby. I used to mainly collect and restore tube based tuners and amps, but recently it has become quite expensive I noticed...
  5. conandrum

    Mute BMW head unit

    Hi all, this is my first post here: Mute button: My BMW head unit has a mute/volume button. The encoder, when pushed-in mutes the head unit. Today, I accessed the encoder and soldered 2 wires on the 2 pins which join when the encoder is pushed-in. See photos/video. Triggering: I have a...
  6. boromyr

    Problem with guitar amplifier: distortions in the higher notes.

    Hello, I am building an amplifier for an electric guitar, and I am encountering an annoying issue when playing the higher frets of all 6 strings of the guitar (Stratocaster) with more force: when playing a string after fret ~19 with greater intensity, the sound distorts, as if it were an...
  7. Q

    Would You Be Interested in an Affordable DIY Lock-In Amplifier?

    During my PhD, I spent countless hours conducting optical experiments, where lock-in amplifiers became an integral part of my research. Their precision and effectiveness were unmatched, but so was their cost. Recently, while doing a personal optics project, I found myself in need of a lock-in...
  8. M

    I made an oscilator, but i need a amplifier to change the amplitude

    I made this oscillator and the output voltage is 1V, and I need another amplifier to go to 5V and some mv ideally to 10mV, but that is harder. I made this but it doesn't work very well and I don't understand why. I can't work with OpAmps, with only transistors. I put a common emitter with a...
  9. J

    Class D Amp - Where in the circuit is the PWM occurring?

    Hello, I have a Class D amplified speaker I am trying to fix (circuit attached). The fault at the moment is that when the speaker is powered on, and with no input signal, one of the speaker channels half-bridge configured FET's begin to immediately overheat. Hot enough that it turns the solder...
  10. BeholdenLemon71

    Is it possible to make an amplifier with the tda8588bj/r1 ?

    I have an old bronken sony cdx-gt207x and I wanna know if it´s possible to make an amplifier with his tda.
  11. violapwr

    Summing Amplifier Channel Isolation Problem

    I'm designing a quad-preamp circuit (for an experimental musical instrument). Each pre-amp channel is read by the analog input of a microcontroller before being summed together. The issue is that there is a ton of crosstalk being reported by the microcontroller between the four channels. I'm...
  12. U

    RF Amplification problem

    Hello, I work on an exercise I made up for myself and I need some help. I want to build a small RF receiver with a central frequency of 50MHz. I made a model of the antenna. I put a band pass filter after it. Both are centered around 50MHz. I want to amplify the received sine with a 7V voltage...
  13. JohnSnow16041992

    100K preset with AD620 instrumentation amplifier good idea or bad?

    So I am planning to use an AD620 instrumentation amplifier in my circuit. The gain formula is G = 1+(49.4KOhm/Rg), Rg being the deciding resistance value. By that logic if a 100K preset or Pot is set to zero, Gain attempted is (∞ + 1), which besides being impossible is also way above the 10000...
  14. kapcina

    Amplifier with 500 voltage gain

    I want you make a amplifier with 500 voltage gain and use a amplifier with common emitter, but I can't get a gain over the 100 with any value of resistors. Vdd is 12 V and b is 100
  15. blink13

    Seeking Advice for Three Stage Amplifier Project: Improvements and Real-Life Feasibility

    Hello, I am a student tasked to build a working amplifier, I do not know much of what I am doing. I've got a three-stage configuration that consists of a single ended differential input stage, a common-emitter VAS stage, and a Sziklai pair output stage. It's supposed to be a 15W amplifier to a...
  16. C

    Need help with FM Radio Transmitter / Amplifier

    So I purchased this : (HanRongDa HDR-831) HanRongDa HDR-831 It's working great but the practical range is about 15 meters. I'm looking to upgrade this. The thing is, I know very little about radio frequencies and antennas. Can something like this work ? Ebay Amplifier The device I purchased...
  17. henry4700

    Clipping Class AB Amplifier output

    Is there any problem of my circuit? How can I fix the clipping?
  18. S

    Need help with identifying the topology of this Amplifier Circuit

    What is the purpose of this circuit?
  19. jcatkeson

    Masuda Electric Dust (Re)mover

    Hi, I'd like to build one of these: https://phys.org/news/2006-04-lunar-buster.html Basically it's a sort of static electricity linear motor that pushes dust around. I understand general principles of electronics and have built a few circuits from kits, but that's about it. I figure this...
  20. K

    Noob question about PS rail

    I'm looking into this (attached) schematic for a bass amp. I'm not sure, why the low voltage supply (+-16V) has his own transformer windings, regulators etc. but then it's connected to the hugh voltage rail? (I've circled in red) Thanks
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