1. StijnC

    Single op amp PWM generator

    Hello, I have to design a single op amp circuit that has only +15v, -15v and GND as input and outputs a symmetrical PWM signal (+V and -V) with adjustable frequency and duty cycle. I have something that works partly but not completely, I can adjust the duty cycle from ±60% to ±100% but af that...
  2. marcoeffe

    Restoring an old RC Lap Counter

    Hi everyone, I'm new in this forum and this is my first post. I'm a software developer but electronics has always been one of my favourite hobbies. I don't have experience in RF circuit design, and for this reason I'm here trying to find someone that can help me in this project. I'll try to be...
  3. Sampler1

    Huntron 1005 Oscillator can we find the problem?

    Hi All, like many the Oscillator died in my Huntron 1005B. as you know they are no where to be found. I came across the old kit schematic and figured I would try and build one. My 1st problem was IC1 and IC2 as they are not identified in the original schematic. I was told by some members to try...
  4. Sampler1

    Identify part in Oscillator Circuit

    Hi, I found an oscillator circuit and there are two parts not identified. IC1 and IC2. The symbol looks to be Zener diodes but There is no value .Would anyone have an idea what they could be? Please see The schematic ,bottom left corner Best regards to all, Stay safe.
  5. C

    How to find total current and phase shift for this Wien oscillator?

    I know that total impedance is Zp/(Zp+Zs) where Zp is parallel impedance and Zs is series impedance that can be calculated easily. Is total current equal to Vin/total impedance?
  6. jxrxmyrxss

    Wien Bridge oscillator not forming clear sinusoidal wave

    This is my running circuit and its waveform. I have met the requirements set by my instructor in which Vrms=2.5 and is operating at <100Hz. My only problem is now making a sinusoidal waveform. I have tried a bunch of things like removing the C2 capacitor and adjusting some of the values but...
  7. fantaasia

    Need help with Crystal Oscillator circuit...

    Hi, I need the simplest circuit to run 250 crystal oscillators at once. The circuit must give a sharp pulse to all the crystals at 1Hz. The idea is the get them all "ring" and resonate with each other. They are regular 32khz cylinder oscillators used in watches. Any ideas?
  8. atferrari

    My first attempt with a Colpitts oscillator - Criticism requested.

    I decided to design a Colpitts oscillator with an output frequency of 1,2 MHz followed by a buffer stage. No other specs for the moment. I would prefer to keep unchanged the coil (I got it salvaged from old radio gear) and the transistors while using a +9V PSU. Once having it working I would...
  9. S

    Need to explain about principle of comparator based crystal oscillating circuit.

    Hi everyone, I am a newbie in electronic field. Now I am trying to design a circuit to drive QCM (Quartz crystal microbalance). In some literature I have seen some comparator-based designs like this: In fact, some similar designs can also be found in the datasheets of high-speed comparators...
  10. Gilsdank

    How to introduce 90 degree phase shift to 555 timer?

    hello, I need to generate 2 signals: a square wave of a pretty low frequency, say 10hz. Right now I'm using a 555 timer to generate the square wave. I also need another square wave 90 degrees out of phase. How can I do this? I've attached a picture of the signals I need. Thank you in advance.
  11. Adrienboub

    VHF oscillator circuit w/ large frequency range and change according to capacitance value

    Hello, It's my first post. I'm new in electronics fields. I'm french and my english is not very good, excuse me. I want to make a VHF oscillator(~ 30 MHz) that his frequency can change with the value of the capacitance. I found in an another post the RF2506 which seems to works but it's...
  12. Mayank_2606

    Can someone explain me the working of this circuit?? Squarewave Oscillator

    I am new to LTSPICE and have been experimenting with designing with op amps as filters and oscillators I recently came around this circuit of a "squarewave oscillator" in LMx58 Datasheet and with an aim to replicate it i decided to use an op amp in the LTSPICE viz. LT1007 to create a similar...
  13. D

    Pierce oscillator simulation on LTSpice

    Hello, I am trying to simulate a 32.768 kHz Pierce oscillator. I am referencing this particular crystal https://support.epson.biz/td/api/doc_check.php?dl=brief_FC-255&lang=en I believe my values are correct, however, the peak frequency of the FFT is almost only depended on the td value of the...
  14. Baio

    555 sawtooth and triangular wave generator: from theory to practice

    Hi, I was looking since some days for a schematic to build a sawtooth and triangular wave generator, then I found this schematic on an online simulator: https://www.falstad.com/circuit/e-555saw.html (I report the original link, obviously, to give credits to the person which has made this...
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