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After following an answer to a question I asked here I created this circuit...


schematic

simulate this circuit – Schematic created using CircuitLab

This is the output on either of the transistor collectors.


enter image description here

Shouldn't I be getting a pretty crisp square wave with this configuration?

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  • \$\begingroup\$ Why should you be? \$\endgroup\$
    – EM Fields
    Jun 10 '15 at 4:40
  • \$\begingroup\$ That's what a multivibrator is? This circuit is designed to switch the transistors on and off in sequence. The diodes and additional resistors are included to decrease rise time by isolating the charging of the capacitor from the current supplied to the collector. Honestly, I'm not even sure what could be going on to produce that waveform. \$\endgroup\$
    – Allenph
    Jun 10 '15 at 4:52
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What you are trying to do is the ROSNER MODIFICATION to the astable multivibrater this was well before the internet and I cant find any reference to it and yes it can sharpen the collecter waveforms A sensible thing for you to do is to increase the caps by a factor of 10 and see some waveform improvement because the astable isn't used at high frequencies

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  • \$\begingroup\$ I've read several examples of this astable at frequencies exceeding 100KHz... \$\endgroup\$
    – Allenph
    Jun 11 '15 at 5:36
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The answer was in the diodes. I went ahead and just used the rectifier diodes I had lying around because at first glance it looked like the diode would only be biased once. Now I realize the bias switches so the 30uS maximum switching speed of a rectifier diode is not enough. I exchanged for a shottkey, and bingo!

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