3
\$\begingroup\$

I'm trying to build a twin-T oscillator for synthesising drum sounds. The LM741 heats up pretty quickly and the circuit hardly oscillates even when the feedback is at 100 per cent. Even with an LM386 amp I hardly get anything (though I can see some oscillation on the scope). The circuit gets 10ms 5V pulses from an Arduino. Does the TL071/2 run from single supply? Can it replace the LM741?

Schematic_http://www.flickr.com/photos/alkopop79/8644385451/

\$\endgroup\$
  • 4
    \$\begingroup\$ 1. Any op amp can run from a single supply. 2. It is difficult to tell what is actually being asked here. Please post a schematic. \$\endgroup\$ – Matt Young Apr 13 '13 at 5:14
  • \$\begingroup\$ Schematics here: flickr.com/photos/alkopop79/8644385451 \$\endgroup\$ – alkopop79 Apr 13 '13 at 12:09
  • 1
    \$\begingroup\$ I suspect a capacitor in series with the output would improve behaviour - at the moment it's effectively DC-coupled the output to ground. \$\endgroup\$ – pjc50 Apr 13 '13 at 12:49
  • \$\begingroup\$ What is the power supply voltage being used? \$\endgroup\$ – Anindo Ghosh Apr 13 '13 at 12:54
  • \$\begingroup\$ circuitlab.com/browse/by-tag/drum Your output loads your (-) feedback loop. \$\endgroup\$ – Optionparty Apr 13 '13 at 14:31
1
\$\begingroup\$

It's working now. I replaced the 741 for a TL072 and a resistor had to be replaced for a larger one (the 2.2M). As for the split rail, I made a simple rail splitter that converts 9V to 4.5V, 0V and -4.5V.

\$\endgroup\$
  • \$\begingroup\$ The circuit here: circuitlab.com/circuit/g52648/screenshot/1024x768 \$\endgroup\$ – alkopop79 Apr 14 '13 at 20:15
  • \$\begingroup\$ You could also checkout LM324 \$\endgroup\$ – abdullah kahraman May 14 '13 at 21:12
  • 1
    \$\begingroup\$ A rail splitters does not convert 9V to +/- 4.5. That's a misleading way to look at it. Your circuit is powered on 9V. Ground is at 0V. What the splitter circuit does is provides a bias voltage reference. That reference isn't a real ground. It cannot sink current like a real ground. You should not use the ground symbol for that node. \$\endgroup\$ – Kaz May 14 '13 at 21:13

protected by Kortuk Apr 13 '13 at 15:31

Thank you for your interest in this question. Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation on this site (the association bonus does not count).

Would you like to answer one of these unanswered questions instead?

Not the answer you're looking for? Browse other questions tagged or ask your own question.