Gated oscillator with 4093 chip

by Stephen Hobley on April 5, 2009

I recently came across a bunch of 4093 chips:

The NAND chip - 4093

The NAND chip - 4093

These are Quad NAND gates, with Schmitt trigger inputs. It turns out you can use these to make oscillators and monostables – just like the 555, but more compact with less parts.

Astable oscillator with a NAND gate

Astable oscillator with a NAND gate

So I updated the oscillator application I wrote to calculate out values using this oscillator as well as a 555. It looks like you can get more of usable range with this device.

Now with support for the 4093 chip

Now with support for the 4093 chip

One thing – the NAND gates cannot source as much current as the 555 timers so you might need to add an opamp as a voltage follower. LM324 does this nicely.

You can download the C# solution here.

One nice feature of the 555 oscillator is that you can connect another LFO signal to pin 5 and create a vibrato effect for even more ‘musicality’ – something lacking with the NAND gates.

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{ 1 comment… read it below or add one }

Harris July 17, 2012 at 12:34 pm

If you add another resistor equal to 3R to the positive leg of the capacitor, you can also use that as the equivalent of a 555 timers pin 5, it modified the frequency and the pulse width 🙂

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