I received 50 TEA2025B amplifiers over the mail today. I ordered these IC’s about two weeks ago at Aliexpress.com. Aliexpress is an affiliate of Alibaba. I have never ordered components from Aliexpress before and I was curious to see how they would perform. Eager to get my hands on these OpAmps I quickly unpacked but […]
After making an improvised coil (experiment 25) and cutting a coil out of a speaker (experiment 27) in this experiment the self-inductance of a coil is demonstrated. As a coil in this experiment I used 44 meters of coated copper wire on a spool. In parallel with the coil two low current LED’s are connected. […]
I couldn’t get the cylindrical neodymium magnet of the required size so I skipped experiment 26. Next experiment 27: Loudspeaker Destruction of Make: Electronics is a very simple and very short experiment but worthwhile nevertheless. It demonstrates how a loudspeaker works by literally cut it to pieces. Luckily I had an old 2 inch speaker […]
About a week ago I wrote about a Darth Vader voice changer that I am making. I finally have finished a prototype but not without problem. I soldered all the external components to the Velleman MK171 kit. When I tested the circuit I discovered that three red push-buttons (see images below) weren’t functioning. I disconnected […]
I skipped experiment 24 of Make: Electronics. The reason is that I’m not really interested (at least not right now) in completing the Intrusion Alarm. I do appreciate what the author of the book, Charles Platt, is trying to achieve. He gives a couple of good hints for upgrades of the Alarm without presenting the […]
First part in a series how to make a Darth Vader voice changer with the HT8950 chip.
I have a lot of tools laying around in a big tool box. The problem is that whenever I need a tool I always end up searching for it. I decided it was time to make a proper tool board. I bought some cheap board (61 x 123 cm). I had some pine wood (9 […]
I recently bought a copy of iCircuit for OSX (9,99 in the App Store. I believe the Windows and Android versions are cheaper). It’s an app to easily create electronic circuit and simulate them. iCircuit is a great addition to my electronics hobby. It’s simple, easy to use and yet very insightful. A started very […]
In this part of experiment 23 of Make: Electronics the binary counter from part 1 is upgraded to a dice simulator (figure 4-109 on page 219). A 74LS27 chip is added. This chip has three NOR gates of which one is used for this experiment. Also an LED display is added. The configuration of this […]
Experiment 23 of Make: Electronics uses 74LSxx chips (TTL chips) instead of the 74HCxx (CMOS) that has been used in previous experiments. In the first part of this experiment a simple binary counter in made (figure 4-102). I ordered some low current LED’s especially for this experiment to be able to see the output of […]