Need to generate 50, 100, 500, 5000, 10000 nanosecond pulse widths, at low frequency ~ 10kHz.
Accuracy of +- 10% acceptable.
Built a circuit using 555, 74HCT221 & 74HCT173 (schematic attached).
Sort of worked in a very rough, unstable, noisy way.
Thought that these problems would disappear when circuit was moved from project board to PCB, no improvement.
Many decoupling caps, 300 Ohm load resistor tried (not shown on schematic) ... still very unstable.
Thoughts?
Accuracy of +- 10% acceptable.
Built a circuit using 555, 74HCT221 & 74HCT173 (schematic attached).
Sort of worked in a very rough, unstable, noisy way.
Thought that these problems would disappear when circuit was moved from project board to PCB, no improvement.
Many decoupling caps, 300 Ohm load resistor tried (not shown on schematic) ... still very unstable.
Thoughts?
Attachments
-
110.5 KB Views: 34