• 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. D

    Stabilising supply of noisy DSO-2250 oscilloscope

    I've had a DSO-2250 9-bit/250MSps/60MHz scope for a decade, bought "new", and it's always had a large ripple voltage (about 1/3 of a division) overlayed on any signal. The ripple sometimes made the DSO barely usable. At some stage I put a filter on the USB cable inline with the power; this...
  2. A

    Stable DC power supply point for Ultra Low Noise Amplifier (ULNA)

    Hello good people, I need help. I'm posting a schematic of an ultra low noise amplifier. It is to be powered by batteries. For that reason, I need a stable DC solution in the place of R4 resistor. I was proposed to achieve that by using another JFET and an integrator circuit, but I am not...
  3. N

    Proximity alarm project

    Hey guys, new to this forum and would really appreciate your help :) I am making an alarm which will trigger a buzzer from about 30ft away and a noise which will help you find the object that you had lost. In perspective I am making a lost and found type of device. Whilst there are similar...
  4. W

    Noisy neighbours, replacing music with CB radio and linear amp

    I have neighbours from hell with music heard in the street 50 meters down the road, the authorities do nothing so I thought natural law and technology would help. Other forums give solutions, but miss full instruction, so I thought I would find technical forums and ask qualified people for there...
  5. Ragooman

    Rusty on Noise problems from SMPS

    I'm a little rusty on noise problems from switching power supplies. And I hope someone can offer some advice. There's this new system which relies on a small +12v smps. This system has a separate controller board mated with a motor controller using board connectors. And the 12v smps connects...
  6. G

    LTspice Thin Film Resistor Simulation

    Alright, my question is pretty simple to ask but perhaps rather difficult to solve. I am modelling in LTspice a channel of previous design and analysing various noise figure across the channel. Currently I am using the stock resistors supplied in LTspice. I was wondering if there is a way to...
  7. J

    Repairing a BWD 521 cathode ray Oscilloscope - no traces, hissing noise

    Hi all. I recently purchased a (obviously) second hand CRO oscilloscope. It worked fine for a couple of days, I was just getting used to it. Then one day, I left it on for 10 mins or so with both traces active on screen. A while later, I heard this high frequency hiss, so I switched it off. The...
  8. N

    DC fans creating electronic noise issue

    Hi! In order to cool a telcom device I am using 4x 12Vdc fans from Delta Electronics (the exact type is FFB0412VHN-F00). The fans have a 3-wire interface and I operate them by sending PWM pulses at their power supply wire. The pulses are generated from a PIC-microcontroller and are "converted"...

Latest threads

EE World Online Articles