The familiar transistor power supply has one big mother of a filter capacitor on the rectifier output followed by an electronic regulator which regulates out all voltage variations including ripple. In vacuum tube days only the very tip top of the line test equipment (Hewlett Packard, Tektronics, General Radio, etc) used electronic regulators. So it was necessary to
Click here to download the full size of the above Circuit.
find a way to filter out most of the ripple using passive components (not tubes). In many devices such as low cost radios and phonographs the designers managed to use resistor-capacitor RC filters but if the current drawn by the circuit was large and the application demanding, such as a Hi-fi power amplifier, the power supply needed an inductor-capacitor (LC) filter. An inductor needs to have many turns of wire wound on an iron core. The wire must be heavy enough to have a low enough resistance so it can conduct the direct current without dissipating an excessive, usually five watts or less, amount of power. The core had to have enough iron in it so as not to saturate at the maximum specified current. Filter chokes are getting hard to find they mostly are seen at electronic flea markets (hamfests) and from dealers on the net who specialize in antique electronic parts. If you`re a retread like me you may have some stored in your basement or garage. It is very likely these old chokes whether in your garage or from a flea market won`t be marked with specifications. Don`t despair. Ve have vays of finding out zese sings. It`s not enough to just measure the inductance of a choke. You need to know how it behaves when carrying a mixture of AC and DC. The simplified circuit is shown here. The transformer isolates the test circuit from the line and provides some step down. The secondary delivers very little Alternating Current but...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
characters left: