As I get more advanced at creating circuits, I can see the benefit to
owning an Oscilloscope. I'm on a fairly tight budget, and was hoping to
get a recommendation on a cheap oscilloscope that is "good enough" for
hobby work. I've used one at school years ago, which probably had more
bells and whistles than I would ever need.
What features are essential for a hobbiest? What can I do without? Any
particular brands that are cheap but reliable?
Thanks for suggestions,
Daniel.
Depends on what you want to do. If you are working at audio
frequencies you probably don't need a GHz-capable scope,
like you would for high-speed digital stuff.
I got by for years with an ancient 10 MHz Heathkit IO-103
that I built from a kit. It was certainly good enough for
the mostly-audio stuff that I was interested in at the time,
and "high speed" digital was only in the low MHz range.
Eventually I worked up to a 100 MHz B&K Precision 1580 (a
"bargain" at $800 back then!) and it's done everything I
needed since.
Now, I'd go with other's recommendations for a decent used
scope.
<shameless plug> In addition to a "real" benchtop scope,
you might want to take a look at my Daqarta software that
uses your Windows sound card. The sound card limits it to
"audio" range, but these days that can be nearly 100 kHz.
HOWEVER, despite what some "premium" cards seem to imply,
sound cards don't go down to DC... so you'll still need that
benchtop scope.
But despite the bandwidth limitations, there are some
powerful features that you won't find elsewhere. The
built-in 2-channel signal generator can create just about
any signal you want, with 4 independent "streams" per
channel. Each stream can be a simple or modulated waveform.
The base waveforms are Sine, Triangle, Ramp (with
controllable slopes that can also be modulated), Square,
Pulse (monophasic or biphasic, controllable phase heights
and widths), Arbitrary (from a file you supply), Play
(complete recordings can be played at any speed, forward or
backward, modulated, etc), uniform White noise, Gaussian
noise, Pink noise, and Band-limited noise.
The modulation options include Burst (with complete control
over rise, fall, duration, lag, and cycle times, and
rise/fall shape), AM, FM, PWM for pulse waves or phase
modulation for others, or Sweeps (which can be linear or
exponential, continuous or stepped). Modulation sources can
be simple sine waves, or can use the output of other
streams. Complete setups can be saved and instantly loaded.
On the input side, besides standard waveform display Daqarta
offers Spectrum and Spectrogram modes. Advanced signal
averaging allows you to extract signals that are buried in
noise, if they are synchronous with a clean "stimulus"
signal. (Used for "evoked potentials" to measure hearing in
animals and infants, for example).
Trigger controls include the usual, plus Hysteresis to allow
you to get a stable view of a noisy trace. Delay allows you
to see events that happened up to 32Ksamples (over a half
second) before or after the trigger. Holdoff allows you to
sync to the start of a burst while ignoring events during
the burst. There is also a Generator sync, so you can (for
example) trigger on an FM modulating frequency.
There is also a built-in frequency counter with high
precision at low frequencies via reciprocal period methods.
Built-in true RMS voltmeter and SPL meters are available if
you calibrate your system.
Daqarta includes a built-in macro language, and now includes
a number of standard "mini-apps" that can be used as-is, or
as the basis for your own applications. Some that you may
be interested in are THD meter, IMD meter, Phase meter,
Chart recorder, and (for fun, mostly) Lissajous figures.
NOTE that after the 30-day/30-session free trial, the
external inputs stop working, but the outputs are not
affected... so the signal generator is yours to keep, for
FREE. (Also file analysis, etc.) So even if you don't buy
it (US$29, or $99 for the Pro version) you might want to
install it on an old laptop and keep it on your bench next
to your hardware scope, with my best wishes. Enjoy!
Best regards,
Bob Masta
DAQARTA v7.00
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Scope, Spectrum, Spectrogram, Sound Level Meter
Frequency Counter, Pitch Track, Pitch-to-MIDI
FREE Signal Generator, DaqMusic generator
Science with your sound card!