Being the sweet n00b I am with a minimum wage job, I went and bought a multimeter from Jameco with autoranging, temperature, frequency counter, etc. Very nice, I particularly enjoy the autoranging, and it appears it's a lot harder to blow a fuse (nice bonus for me). Anywho, I rigged up a 555 circuit to test out the frequency counter, got a signal well above 5 Hz (the minimum), hooked one clip to the end of the LED which was blinking at the time, and the negative to ground. Is there some other trick to this? It's not working...
Did you clip it to the correct leg of the LED? Is the frequency counter supposed to work with the voltage of the LED you tested on? The ones i have seen use TTL levels, meaning a standard red or green LED could have a too low voltage for the counter to work.
what circuit are you using for the 555, some circuits i have built give a horrible saw tooth wave (using scope) but others give a much nicer square wave.
It's this one: http://www.play-hookey.com/digital/images/timer_555_astable_sch.gif Off Play-Hookey.com. Though I've slightly modified i with a few capacitors and transistors to try to get it to play nice, still no luck. Probably a nastly looking wave like someone said, but I have no real way of looking at it, and my multimeter polls too slowly to see anything much.
