teardownit

  This is a piece of circuitry magic; it's a great pleasure to assemble and configure it! The receiver sounds pretty good if a medium-wave station is nearby or an AM transmitter is at home. In the previous post, we've assembled an eight-transistor AM MW superheterodyne. This is an excellent, straightforward solution for reliable, high-quality radio reception. Still, the scheme is a bit too complex for a beginner. A few decades ago, it was also not budget-friendly; it was three times more expensive than a tube All American Five (midget, peewee) radio. Simpler amateur DIY receivers were more common, using one or two and sometimes up to three transistors. Today, we will assemble and look into one of those schemes. By the way, if you experiment with vintage tube radios and TVs, remember that many are powered directly from the mains without a transformer. That means the chassis and all components could be under high voltage relative to the ground! Peewee radios often came with a spe

  The LRS-150-24 power supply can operate from a 100–120 volt or 200–240 volt AC network. The manufacturer states it provides an output current of up to 6.5 amperes at 24 volts. The supply measures 5¾ × 3¾ × 1¼ inches (145 × 95 × 30 millimeters), made on a fiberglass printed circuit board fixed to the base's case. The top cover is perforated in a honeycomb pattern. The case and cover are both made of aluminum. The board is put together neatly, with no visible defects. The components are arranged evenly, and soldering was done with a no-clean flux. Absolutely nothing dangles or rattles in the assembly. No noises of any sort were noticed during the operation of the power supply. The power supply uses a flyback circuit without PFC. The input voltage is supplied to the input node: RF interference filter (1), a pulse surge limiter (varistor), then the voltage goes to the diode bridge (2) and two input electrolytic capacitors (3). The input voltage selector is also located here. Flyback,

"PiEBridge" is an extension board for microcomputers similar to the Raspberry Pi (Pi), which is designed to be a helper for the DIY-maker in all his activities - Pi, together with PiEBridge, can perform a variety of functions: universal programmer software and hardware debugger for target systems PCB fusion furnace controller smart-home controller as well as do many other useful things You might say Pi already knows how to do these useful things, so why does it need more extension boards? Here is the answer to that question: PiEBridge transforms the Pi's 40-pin I/O subsystem into more practical 6/10-pin lines for many applications and provides signal integrity for these lines adds the simplest controls and indications (button, pedal, and LEDs) has a programmable 2.5...5V power supply for external devices "Naked" Pi is usable in two extreme configurations - either just a box controlled externally via SSH or a desktop computer with a monitor, keyboard, and often e

The accuracy of reflectograms, the reliability of the conclusions made, and the time spent on diagnostics largely depend on the set of additional functions of a particular device. A modern reflectometer must meet the following requirements: • have a decent amount of memory for storing reflectograms with workable resolution; • be able to exchange data with a computer; • have two channels for comparison and differential mode support; • automatically calculate the return loss value. Other useful features that make the operator’s job easier, thus worth mentioning: • automatic search for defects when viewing a reflectogram; • automatic two-dimensional scale adjustment to fit the most significant defect found; • distance measurement between two points or cursor positions on the reflectogram; • registering transient or "non-persistent" faults. Introduced as another means to simplify the operation, some of the functions mentioned above had a revolutionary impact on fault localization