Extremly simple 300-500 kHz short duty pulse generator circuit

[dieter]

This circuit is extremly simple and cheap. It uses a standard 555 and a CD4093BE, which is a NAND gate.


The 555 is wired to achieve max speed, this may be above 300 kHz, increasing slightly from 12 to 18 V.
555 needs 6 to 18 VDC.


The signal has a very short low time, which is why, it is simply inverted by the NAND chip. After reducing the current from pin 3 to about 5mA (i think it's 840 Ohm), be feed it into both inputs of the first NAND GATE. Then whenever the signal goes false (low), the condition and output goes true (high), and vice versa, basicly inverting the signal. A NOT gate, without the fuss of dealing with lots of to be adjusted parts. After a Resistor (do not draw too much current from the NAND chip, they blow up easily) I have here an LED, but you could also use this at the base of a transistor, or a Darlington + Power Transistor stage.


Unused Inputs of the CD4093 must be connected with Minus/Ground. They are a bit sensitive, never draw to much current, so a 1kOhm resistor or higher is recommende, before you do something with the signal. The pulse duty is very short, I would guess about 4%.


I thought I share that, since it's so simple.

[TinselKoala]

Can't you make your photo any larger? I'm having trouble counting the dust particles for my replication.

Resistor looks like 820 ohms, 10 percent.

[dieter]

Tinsel, you're welcome. Try to stay within +- 10% of the dust particles, which should work fine. And s for the Spaghetti Sauce splashes, try to substitute with ketchup, if Bolognese is not at hand.


Try to be more optimistic. You can do that!

[citfta]

Free Photo Converter allows you  to resize your photos to match the requirements of this forum.  It is very simple and easy to use.

[dieter]

Get a grip it's 1.3 MB, and for the first time ever you can actually see every important detail.


Yeah it may blow up the layout. Take it or brake it. If anybody is interested in the circuit, he'll be glad it's so detailed and sharp.


NOTE: forgot to mention: frequently check temperature of the chips (but don't touch the legs). If they're getting real hot, lower input voltage and/or output current. If it's still getting too hot (too hot to touch comfortly), choose an other design with a lower pulse rate, see also "50 555 Circuits" by Colin Mitchell.