I bought this book, have all the bits and am trying to follow along. I'm on chapter 5 (IC's) and implemented the flashing LED circuit in Fig 5.2. I've implemented the circuit in Fig 5.6 where the LED is replaced by a resister and capacitor. Problem is, I get the same results, except for when I substitute the last capacitor (1nF). I just don't get the 4.2V or 4V from the next 2 experiments, where C2 is
100nF and 10nF respectively. I've no idea why, either. Now, the capacitor I'm using says 1n0K63 on it and I'm sure that is the same as
1nF = 1n0 = 1.0nF, right?
ASSuMEing that everyone (or, indeed, ANYone) has that book is quite an imposition on the group.
The way to get good help is to put up a copy of the *schematic* here so that EVERYONE can see it.
One way (the easy way) to do that is
1) Make a *.GIF or *.PNG of the original using a scanner or digital camera.
2) Upload that image to a "image hosting service".
formatting link
*-*-emphasis-on-free-speech+registration+limit+Last+uncensored+Image.Ho= sting&strip=3D1
3) Put a hyperlink to that image in your Usenet post (this is NOT "Google Groups")
formatting link
*=-a-service-for-*-*-*+Usenet+*-Wikipedia+hide.the.fact+*-*-policed+concerns-=*-*-*-*-about-the-Google-interface+*-*-follow-Usenet-customs-and-*-rules+*-=*-*-not-*-mustered-*-*-*-*-*-*-*-*-*-*-*-*-*+*-*-*-*-*-*-*-software+less-*-=savvy-*+*-*-*-*-*-*-*-*-*-*-*-*-is-now-legendary+zzz+*-summary+qq+Web and _deep-link_ to the **image**--NOT to the *page*. . . Another way (a BETTER way) is to use ASCII characters to draw your circuit within your post:
The following ASCII can be cut n pasted into a new file and loaded into LTspiceIV, it's probably not the neatest, but I couldn't find a way of rearranging the pins on the 555.
You didn't include a ground on the schematic and LTSpice kind of wants that placed somewhere in order to simulate it.
As you have it, C1 participates in setting the period. You didn't specify a value on the schematic, so I just used 10uF as a default. C2 modifies the tau (duration) of the pulse you observe on an oscilloscope. If you are using a multimeter, though, you are probably going to have a hard time observing it unless C2 is pretty large and even then you will "observe" some kind of averaging, probably. Do you have a scope or logic analyzer of some kind to use? That may help a lot with looking at the results of what you are building.
C1 is switched between 10 microF, 1 microF, 100 nF, 10 nF and 1 nF. In his results, he gets 0V, 0V, 1.5V, 4V and 4.2V respectively, this is when C2 =3D 100 nF. I match these results except for the last one where I get something like 0.14V. My multimeter is set to 20V AC range.
Also, when C2 is 10 nF, he gets: 0V, 0V, 0V, 1.5V and 4V for the above, again, my last reading doesn't match.
if you plot the FFT of your output voltage with your LTspice, you'll see that with C1=3D10n, the output frequency is about 5.8kHz but if you change the C1=3D1n, the FFT will show your output frequency is about 57.4k Hz. most of the DMMs will have a AC frequency measuring range. some 30kHz even less. so there is high probability that you DMM is not rated for that high frequency measurement. check the spec on that. it's best to use a oscilloscope or analyzer for this type of measurement.
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