Show the homemade equipment you are using now.

[MathWizard]

(Stretching the meaning of “using now” a little.)
                                                                                                                 
Upper photo:
                                                                 
BC band generator (1959)
Oscilloscope (1961)
Variable AC and +/-DC power supply (1973) on top of
1.3GHz generator (1976)
Oscilloscope (1976)
Sound level meter (1980)

Lower photo:

Trombone air flow meter (2019) on top of
4-output power supply (1988)
Fast square wave pulser adapter (2017) on top of
Focal plane shutter tester (1997) on top of
Wow and flutter meter (1998) and                                                                                       
Low distortion audio generator (2019)                                                                                         
Semiconductor curve tracer (2021)

Hey ccktek, seems you've been at this while LOL. What sort of curve tracer did you make in 2021 ?

[ccktek]

MathWizard, thanks for your correct observation and inquiry.

https://www.eevblog.com/forum/projects/self-contained-semiconductor-curve-tracer/msg3551423/#msg3551423

[Zero999]

A dual tracking +/-15V LM317 & LM337 power supply. I've just noticed there should be a centre tap on the transformer in the schematic, but otherwise it's correct.

[MathWizard]

MathWizard, thanks for your correct observation and inquiry.

https://www.eevblog.com/forum/projects/self-contained-semiconductor-curve-tracer/msg3551423/#msg3551423

Yeah it looks interesting. I've have a couple of old transformers lying around that I plan to use in a real CT.



I've made a few little circuits on proto-board over the past few years, that are like my home-made tool box. Like an H-bridge tester for small motors, a TRIAC/SCR tester, an 11M resistor box, a wire tracer/ finder, a RF probe/signal tracer, resistive load testers on boards, etc.

I built a copy of an old linear 30V, 1A PSU.

Now that I have a bit of money, I need to start making better stuff. Like a better op-amp controlled PSU, a 1/2 way decent curve tracer, and modular high power, high current load tester for some computer PSU's. I need to start looking locally for good transformers and heat sinks. Otherwise I'd have built some better by now along those lines.

But I really want to learn some more theory, so I don't just copy exactly another design. But I would try to copy some older stuff like Heathkit.

[inse]

@ MrYakimovYA #36 Reply
Do you need special connectors and cables to handle 100GOhms without compromising the measurements?

[MrYakimovYA]

@ MrYakimovYA #36 Reply
Do you need special connectors and cables to handle 100GOhms without compromising the measurements?

No, I have no triax cable, so I use just a common coax. The metallic shield, metal case are used as a guard. So I can't see any problem. I tried to draw all these ideas at the attached picture) Where Il@Rl1 - leakage current throught RL1; IL@RL2 - leakage current throught RL2.

RL1, RL2 - leakage resistance of input and output coaxs.

All ideas had been taken from: https://www.tek.com/en/documents/product-article/keithley-low-level-measurements-handbook---7th-edition

[MrYakimovYA]

I use it quite widely. I check the ability of something with linear transformer inside to work from wallet outlet. I also can have a high voltage to check leakage current or measure something above 1G, for example.

[Njk]

It took a time to locate it, but I did. Because of peculiarity of the thing.

Compact water-cooled rectifier CWCR-001, of my design. For testing a 12/24V automotive stuff (DC motors, etc.) in the lab. Features:

- small form factor, easy to keep when not in use;
- 10A diode bridge inside;
- ISO 4165 DC output socket.

Before use, put it in a jar with cold tap water. Watch the temperature, replace the water when necessary.

Machined from an aluminum piece by my best manufacturing partner, a decades ago. Developed some internal rust (stainless screws were not available) but still works.

[vinlove]

AD9850 DDS RF generator kit.  This was simple and easy build needing just a soldering iron, wire stripper, plier, nipper and screw drivers.

About 5- 7 years ago when I had an old Ten Tec Omni with seized up VFO, this unit connected to the external IF port of the Omni, and drove the TenTec nicely making tons of HF contacts.  The TenTec Omni had been sold, but this self built AD9850 DDS VFO controller / RF Generator is still here.  It had not been used for few years now.   I am planning to build a HF receiver using this kit.

[amc184]

I built a couple of USB to UART adapters because I wasn't that happy with what I could find off the shelf.  One is isolated RS-422, with DC to DC converters to supply the device side.  The other is plain UART, with the option of host powered 3.3 or 5V levels, or isolated with a device defined level.









Both use a CoreChips SL2.1A as a USB hub and a Holtek HT42B534-1 USB to UART converter.  I chose both because they did what I needed and were simple to implement.  I used an Analog Devices ADUM1201 for the isolator, and a Sipex SP490 for the RS-422 version.  They work well now, but I had to do a couple of spins to get them right, and spent way more time than I should have on a side project - the story of my hobby.

[Miti]

The frequency counter is not used anymore but the others are.
1. Universal soldering station, Unisolder designed by Sparkybg. It can take (autodetect) pretty much any iron. This is my main soldering station.
2. LC meter for small parts, pF-nF, nH-uH.
3. Thermometer, barometer with PIC16F946 and LCD. I designed this to understand better how to use the PICs with LCD drivers and to see how low power I can go. The 300mAh battery lasts about a year and couple of months full change, a reading every 3 seconds.
4. Frequency counter 100MHz. It has auto blank zeros, auto decimal point, units indicator, period, etc. All gates and counters, no MCU rubbish. I designed and made this when I was in highschool.

[BillyO]

Just made a set of Thevenin lead today.  14 gauge silicone insulated wire.  These will simplify 4-wire measurements / power supplying / loading / etc..

[py-bb]

GPIB / USB adapter.

Schematics and part list please!

[Bud]

It may not be useful to you, because it was a custom design and would not be supported by the usual computer side software and  libraries. I wrote my own for it. And the PIC on the board had a custom firmware that handled communication with only a few old HP instruments that I had at the time, it was not a generic adapter.

[MrYakimovYA]

My Resistance Set Standard. There are precision soviet union S5-60 (C5-60) and MRH (МРХ) resistors inside. It's in testing stage yet... I'm investigating its specifications))

[Vgkid]

That looks nice. I had plans for a similar idea.
Pics of the internals.

[Njk]

Another related things from my museum.

1. A combo device that integrates the three functions in the welded aluminum housing:
- 6V AC PS for soldering iron;
- curve tracer for testing the integrity of a 74xx logic I/Os without having to de-solder the chips from the PCB;
- 5V 1A general purpose trimmable DC PS (LM317).
Proved very useful for field troubleshooting of a PDP-8/PDP-11 mini-computers at the component level.

2. Metal is not the only construction material. Plywood is more eco-friendly one. A wooden PSU of the bench type (left). Don't show it to a firefigther but eventually it made a contribution to public safety. First OnStar automotive boxes were powered from this unit during the development time. Tor trafo + minimalistic design = space saving (convenience). Compare it with a full-blown commercial PCU on the background.

3. Sensor board signal simulator. Generates a project-specific pulse patterns from an input sine wave. Lot of 54xx chips. A golden heritage...

[cgroen]

Rotorcontroller (Az/El) control for my satellite system (and soon EME system)
All done from the bottom, hardware and software (except the power drivers, these are plugin modules as I had expected they could at some point go "puff", so far they have not )
(more pics etc: https://www.moonbounce.dk/hamradio/ham-radio-current-systems/rotorcontroller.html)

[Njk]

Rotorcontroller (Az/El) control for my satellite system (and soon EME system)

I like the antenna motor drive you're using. How frequently you have to service it?

[cgroen]

Rotorcontroller (Az/El) control for my satellite system (and soon EME system)

I like the antenna motor drive you're using. How frequently you have to service it?

Thanks,
so far it is running flawlessly! Current draw was a bit higher when we had -11 degC, but that was to be expected (approx 1000 mA compared to approx 400 mA).
Have had it in use for 5 months now (heavy use, every day)

[py-bb]

It may not be useful to you, because it was a custom design and would not be supported by the usual computer side software and  libraries. I wrote my own for it. And the PIC on the board had a custom firmware that handled communication with only a few old HP instruments that I had at the time, it was not a generic adapter.

It may still be please! I have some LeCroy stuff and software I wrote with serial ports, not realising that it takes 700 seconds to dump all the channels at the thing's top baud rate - so... I'd really love a look

[MrYakimovYA]

That looks nice. I had plans for a similar idea.
Pics of the internals.

A bit of horror is inside. As I said earlier I'm testing it. And I'm collection a bunch of notes what to fix. A lot of wires, for example, must be tied to each other with a nylon tie. Some solder connectios are a little ugly. And I'm going to replace 100 kOhm and 1 MOhm decades with a more stable S5-60 (с5-60 in Russian) resistors instead of MRH (МРХ in Russian) type. I'm awaiting them via the post from another city.

[jasonRF]

This is a ~6 dB,  ~5 MHz amplifier I built with selectable 50 Ohm or "0" Ohm output impedance.  I originally designed it to use with the 100 kHz signal generator built into my Picoscop 2204a, which has a 600 Ohm output and is limited to +/- 2V output.   It is AC coupled on input and output and is almost exclusively used for sinusoids.  My original design used opamps and would have been simpler and better, but this was more fun   

jason

[MrYakimovYA]

This is a ~6 dB,  ~5 MHz amplifier I built with selectable 50 Ohm or "0" Ohm output impedance.

Nice work! It looks so nice! Could you tell me what is its noise level?

[Bud]

It may not be useful to you, because it was a custom design and would not be supported by the usual computer side software and  libraries. I wrote my own for it. And the PIC on the board had a custom firmware that handled communication with only a few old HP instruments that I had at the time, it was not a generic adapter.

It may still be please! I have some LeCroy stuff and software I wrote with serial ports, not realising that it takes 700 seconds to dump all the channels at the thing's top baud rate - so... I'd really love a look

I made mine in 2012, here is a link to the author's web page, seems he released several updates since then.
But he said the speed is 57600 baud.

http://dalton.ax/gpib/