| ??? 01/10/09 18:52 Read: times |
#161409 - How stabile is your signal source? Responding to: ???'s previous message |
What components she used in 555 for getting the 780 Hz matters.
she may have to use precision resistors and Box type capacitors as use of ceramic as in the timing might cause problems. I had this problem while making an LCmeter2using PIC16F628 design by Phil Rice of Australia. When I resorted to 1kpF 1% box cap from M/s Farnell, I got wonderful stability that was needed for the project this is in addition to all expert comments given on the subject. Perhaps she could use some high frequency crystal oscillator with divider as a standard source, and try to repeat the experiment. I also doubt the accuracy of 1 Sec delay routine and perhaps it needs to be fine tuned and oscilloscope test may not be correct. Sarma |
| Topic | Author | Date |
| Frequency (Event) Counter Problem | 01/01/70 00:00 | |
| less than 1% error | 01/01/70 00:00 | |
| Error % is incremental. | 01/01/70 00:00 | |
| ;STARTING BOTH THE TIMERS AT THE SAME TIME | 01/01/70 00:00 | |
| Less variations in TL0 but still error | 01/01/70 00:00 | |
| I do not know, but | 01/01/70 00:00 | |
| CRO Frequency Measurement | 01/01/70 00:00 | |
| Better But Still An Issue | 01/01/70 00:00 | |
| How stabile is your signal source? | 01/01/70 00:00 | |
| Very Good Point... | 01/01/70 00:00 | |
| Easier if 89c52 is used | 01/01/70 00:00 | |
| How stabile is your signal source? | 01/01/70 00:00 | |
NE555 is popular but not a precision device | 01/01/70 00:00 |