The following scheme is the clock generator circuit diagram which build based on NAND Gate logic IC. You may use IC 7400 or 4011 for this circuit. The 7400 is a Transistor-Transistor Logic (TTL) type, while 4011 is Complementary metal–oxide–semiconductor (CMOS) type. IC 4011 is cheaper than 7400 but the 7400 is faster than 4011.
Circuit Notes:
- Excellent clock generator to drive 4017 type CMOS circuits.
- R1 = 10K to 10M, C1 = 100pF to 47uF.
- Fo is ± 1KHz when R1 = 100K and C1 = 10nF.
- You must use regulated 5V input voltage for 7400, while CMOS 4011 can be from 5 to 15V. Regulated power supply with LM7805 will be great to supply this circuit (with 7400).
Below images are the pin assignment for NAND Gate TTL IC 7400 and NAND Gate CMOS IC 4011:
Better to use a Schmitt trigger IC to do this. 7414 etc
2018.11.28
I tried to repro this circuit with an [SN 74 LS 00 N, by Texas Instruments], but even with a 47uF and 5MOhm resistor, the frequency seems to be around 175MHz to 200MHz (which is purely estimated since by scope is officially limited to only 100 MHz) AND the signal voltage and is sinusoidal and is always under 2.0V (doesn’t trigger even a little bit below that) which is the logic level for a High accordingly to the datasheet. The cap is electrolytic, but the same behavior seems to be repeated for a film cap (1uF though) or for ceramic caps. Is there a counter indication about this circuit for the LS category of the 7400 chips? My wiring seems ok (on a breadboard), being able to trigger the right outputs accordingly to the proper inputs. I know that there are other possible circuits out there, but I am particularly interested by this one only, and wish to know it I have to forget it completely, or if there is a “fix” or if someone is with an idea to keep the basic idea of this circuit.