DIY Test equipement

[slash14]

Hi everyone !

I'd like to know if some of you have already done their own test equipement.

Do you know what test equipement can be realized "at home" ?
Distorsion meter ? Spectrum analyzer (only the audio band, what would we do with a 30GHz bandwidth ! ? ) ? Impedance meter ?
and such ...

Thanks for your replies.

 

[Mark Burnley]

Hi Slash,

Well...I've built a lot of test equipment over the years, but in order of day-to-day usefulness:

1. Bench PSU- +/- 0-24V variable, with fixed +5, +9 and +12
2. Discriminating audible continuity tester- different "bleeps" for 0R and diode-junction drop. Handy for fault finding.
3. Squawk box- battery powered amp with hi-Z input and variable gain. Great for signal tracing and hum finding.
4. Balanced/unbalanced breakout box
5. Battery powered buffered and range-switchable VU meter.
6. AC-millivoltmeter. Hi-Z input and battery powered.
7. Variable DC load- 0-5A current souce/load.
8. Breadboard with built in +/- variable PSU and +5V for logic etc. All connectors- XLR, jack etc built into baseboard with PSU.
9. CMOS/TTL logic probe.
10. Battery powered go/no-go transistor tester.

That's years of working on a budget and needing gear to get a job done- I've also built cap testers and impedance bridges, but the advances in DMM's make them pretty much a project to build for interest/learning now!

Most of the above projects were built from scratch, or from designs I've found in books and elec mags and adapted.

A bench PSU has to be top of the list though!!

:thumb:

Mark

 

[Rob Flinn]

I`ve made

1. AF signal generator
2. variable 24v PSU with current limiting
3. Logic probe
4. bipolar PSU.

Sometimes I`ve got deals on ready built test gear that have made it uneconomical to diy. For example £15 on a regulated (using an EL34) variable valve bench PSU, & £10 on a valve voltmeter

 

[ijr]

In Russia, it is common to built dmm's, power supply's, oscilloscopes.....
For example, at age 14 I catched first place on respublic's exibition
of works of "young tech's" for 10-digit frequency counter
based on like 20 primitive counters/trigger's/or's/nand's&etc.
in box ~12x20x5 cm (without power supply), made on
hand-drawn DUALSIDE pcb :shock:
(not mine design of course, I just did it from magazine design)
with additional stuff to measure U/I/R.
Now, people in Russia make same things on PIC's, but nuffin' changed
since )
In Israel, you have enough money to buy or buy and modify.
One thing I really found not very "buy'able" is good low distortion test oscillator.
I did one from Linear Technology, appnote43.
Used with tweaked up a bit 334, it is possible to measure 0.001%thd,
and with homebrewed passive t-filter (based on hardtofind dual multiturn
pot) it is possible to measure deeper a bit and see what happens on screen of hp3582.

 

[NewYorkDave]

Let's see... I've made some oscillators, some simple bridges, a couple of V-I curve tracers, load boxes, etc. I even made a manual-nulling distortion analyzer, but the notch was TOO narrow--it was hard to tune. I kept meaning to modify it with a "fine adjust" pot, but I never got around to it.