Hobby Electronics Basics

Need help identifying and locating DIP-packaged trimpot resistor

Aloha! I'm reverse engineering an early 1980s era PCB. On the board is this DIP-packaged trimpot resistor. Its dimensio...

11 comments posted 9yrs

posted by groink1

11 comments posted 9yrs posted by groink1

sequential transistor relay

Good Day Sir/Ma'am, I'm a technician and I am in need of schematic diagram of a sequential four transistor driven relay...

1 comments posted 9yrs

posted by mcgyver009

1 comments posted 9yrs posted by mcgyver009

Cables and Currents

This may be a stupid question, but here goes. We all know that cable is graded for its current carrying capabilities ac...

23 comments posted 9yrs

posted by cbx

23 comments posted 9yrs posted by cbx

Cheap oscilloscope kit

I recently built the JYE Tech DSO-150 Shell oscilloscope kit (#15001K) that I got from Banggood for $24 plus a power su...

6 comments posted 9yrs

posted by waybackNO584SPAM44

6 comments posted 9yrs posted by waybackNO584SPAM44

Bipolar current limit

OK this is perhaps overkill.. see footnote. So I've got an indicator LED (bi-color) the input is the error term from a...

27 comments posted 9yrs

posted by gherold

27 comments posted 9yrs posted by gherold

Connector rant

Sorry I spent part of the morning looking for a connector.. pcb-pcb right angle. So why are connectors more expensive t...

12 comments posted 9yrs

posted by gherold

12 comments posted 9yrs posted by gherold

relay circuit

Hello- I need help in designing a circuit which would take an input from any of 3 momentary switches and then operate a...

9 comments posted 9yrs

posted by rk.covell

9 comments posted 9yrs posted by rk.covell

Electric Motor Cost/Watt Is Impervious To Size

There doesn't seem to be much in the way of economies of scale when it comes to the cost/watt of electric motors. Most...

4 comments posted 9yrs

posted by bretcahill

4 comments posted 9yrs posted by bretcahill

Question about soldering iron tip

I have a plain 30-watt pencil iron. It's this one: https://www.amazon.com/gp/product/B00KXX6RLA/ The tip is almost 3 in...

17 comments posted 9yrs

posted by waybackNO584SPAM44

17 comments posted 9yrs posted by waybackNO584SPAM44

Links for DIY boost convertor and Joule Thief

I'm trying to learn about these. I thought I would share. https://www.youtube.com/playlist?list=PL4Eg18Oxse-_Vz7uSH7ZpWT...

3 comments posted 9yrs

posted by weddingabc2015

3 comments posted 9yrs posted by weddingabc2015

Unfamiliar FET and capicitor schematic symbols

In the simplified schematic for the Analog Devices AD825 there are two symb ols I haven't seen before. One of them is a...

12 comments posted 9yrs

posted by scott.hall

12 comments posted 9yrs posted by scott.hall

How is one volt defined?

Just curious about it. Does every country have its own devices to calibrate one volt in meters? -- @~@ Remain silent! D...

14 comments posted 9yrs

posted by toylet.toylet

14 comments posted 9yrs posted by toylet.toylet

Dielectric Grease

I had a poorly soldered wire acting up. I smeared some Permatex tune up grease on it and it solved the problem. It does...

18 comments posted 9yrs

posted by bretcahill

18 comments posted 9yrs posted by bretcahill

Lumen / $ Ratio Up to 800 With Dollar Tree LEDs

Admittedly this ratio isn't as famous as earnings/dividend but . . . Bret Cahill

2 comments posted 9yrs

posted by bretcahill

2 comments posted 9yrs posted by bretcahill

Tube (valve) amp really works!

Some time back I posted a question or two about this tube headphone amp: http://oatleyelectronics.com/files/K272X.pdf ....

39 comments posted 9yrs

posted by etpm

39 comments posted 9yrs posted by etpm