An adjustable regulated power supply is a necessary tool for an electronics laboratory. Here is a laboratory power supply 2.7-30V up to 4A I built has worked for 30 years ago and still going strong. Its function is to supply a stable voltage set by the voltage control potentiometer up to the current set by →
Some time ago I saw The ultimate VGA to SCART adapter project at Hackaday with description: Accurate recreation of vintage arcades is becoming increasingly difficult. CRT monitors are rare nowadays and, even if you find one, it will probably not support the 15.7Khz horizontal frequency used by many old arcades. A good alternative is a →
DMX512 (Digital Multiplex) is a standard for digital communication networks that are commonly used to control stage lighting and effects. It was originally intended as a standardized method for controlling light dimmers up to 512 dimming channels. The first standard version was created in 1986, with subsequent revisions in 1990 leading to USITT DMX512/1990, ANSI →
There has been questions like those on 2600 magazine Facebook group: How do you prevent your phone from being used as a bug so malicious individuals can spy on you? What’s the best way to temporarily block/disable the microphones in an iPhone. Does anyone know of a phone case with a built-in shutter? The idea →
I have understood that hooking up an old telephone handset to work with a cell phone is simply a matter of connecting together the correct wires. You need to wire the microphone and speaker in the old telephone’s handset to the microphone and speaker in the cell phone’s headset connector. I decided to try that →
This is a continuation to my recent potato chip to TDR circuit posting at http://www.epanorama.net/newepa/2018/10/16/potato-chip-to-tdr-circuit/ Here are some measurement results made with high speed oscilloscope (at shortest pulse setting and 50 ohms impedance). Blue measurement with circuit directly connected to scope and yellow wirh 10x scope probe. →
A time-domain reflectometer (TDR) is an electronic instrument that uses time-domain reflectometry to characterize and locate faults in metallic cables. I designed a TDR circuit many years ago for easy cable testing with oscilloscope: That circuit was also turned to an electronics kit that is sold by Far Circuits. When getting the original 74AC14 seemed →
This article talks about measuring 10 Mbit/s (10Base-T) and 100 Mbit/s (100Base-TX) twisted pair Ethernet signals. Those standards use two wire pairs for the communications and use differential signaling. Differential signaling is a method for electrically transmitting information using two complementary signals. The technique sends the same electrical signal as a differential pair of signals, →
This article can be seen as continuation to my Powering microphones document and PC microphone phantom powering improvements blog posting. Jon Blackstone said in comment: Tom – I’ve got a solution for this that’s very simple, and is working for me. I connect the ECM capsule (cheesy computer mic) directly to pins 2 and 3, →
Pulse generator is an electronic test equipment used to generate rectangular pulses. Pulses are typically injected into a device that is under test and used as a stimulus or clock signal or analyzed as they progress through the device, confirming the proper operation of the device or pinpointing a fault in the device. Typical application →