1. Lucky-Luka

    Simple Temp Sensor Circuit using TMP36 and LM358

    Hi all I have to monitor the temperature of a surface for several hours per day. The circuit will be battery powered. I already have a LM358 op-amp and a TMP36 sensor at home. I thought 4x AA NiMh batteries (1.2V) are ok. I just want an LED ON when the temp is over 50 degrees Celsius and...
  2. Klodo

    Lm358 as an RF "amplifier" : possible ?

    Hello , can we amplify a small signal of 433Mhz by an amplifier based on an lm358 (which its 700khz of BW) ?? I got this question while watching this video (in the video the guy went even further than my question; he made it into a mobile phone wave detector) ; Thank you in advance for...
  3. Philexium

    LM358 single voltage : how to reduce offset voltage ?

    Hi, I have built a VHF field strenght meter (144 MHz). The operational amplifier used is a LM358. I need the strenght meter to be very sensitive ! Due to the high gain (about 1 000), the offset voltage is multiplied too and so without any HF field the needle of the 100 ua galvanometer is...
  4. R

    Simple non inverting op-amp circuit to amplify mic sound don't work

    Hi all Considering this simple circuit When I connect it as shown the sound became amplified for 2 seconds then it stops. So I have to connect the jack to pin 3 instead of pin 1 .. how to fix this Thanks a lot.
  5. Azusau

    Audio noise with MIC

    hi, I had try to use LM358 and TDA2822 to finish a audio circuit that shown as below. Now, here is a trouble that a lot of noise when I using MIC input audio signal, but it looks normal work when I using my cellphone input audio signal. there are two videos show the two condition. Audio signal...
  6. Ford Prefect

    LM358 Test circuit

    Hi guys, I tend to use quite a few LM358's in several of my circuits but I have come across some LM358's which have been faulty. I have soldered them into my circuits and after discovered that the LM358 is at fault then have the annoying task of unsoldering the LM358 and replacing it with...
  7. xavseg

    LM358 VCO Problem

    Hi everybody !! Well, I recently made the famous LM358-based VCO as in this article : https://www.allaboutcircuits.com/projects/diy-synth-series-vco/ Everything seems to work fine except those buffers which I can't get to work at all and I just can't understand why ... I've already tried...