Basic Regen design is pretty common, so BEFORE the schematic comes the `concept stage`, the `what`s available in the junkbox stage`, back to the `concept stage`, followed by the `mechanical/electrical layout stage`, then sketch a rough schematic. and do it all over again. The BC-221 has always impressed me as having about the simplest, smoothest,
Click here to download the full size of the above Circuit.
no backlash, tuning mechanism which is readily available to us. In fact, I picked up another two beat up BC-221 derivatives (forgot the numbers) at the last swapfest, one for $5 and one for $7. can`t beat that for really good parts including the covers. This is a Regen and all Regens should be breadboarded on a piece of plywood (personal opinion based on my first experience). An 8" x 9" breadboard looks about right and will fit inside the diagonally cut covers of and old BC-221 derivative (see the picture). The tuning mechanism and variable were mounted on the "front" panel and the panel was reinforced with extra ribs to reduce flexing. Having both the tuner mechanism and the variable capacitor on the same panel prevents additional movement. Selection of a good "solid" coupler and alignment of the 2 shafts is important. If you use shims, you still need solid mechanical mounting and aluminum is easy to work. After measuring the coil with my invaluable AADE L/C Meter and doing a little figuring, the coil I had picked out should cover the desired frequency range with 4 taps and a smaller value tuning capacitor for the higher frequencies. Molex connectors were chosen for the taps because they are a good connection (better than a clip), cheap, and provide the shortest lead length. The coil was located to give the tuning capacitor plenty of room and to allow for installing a shield if necessary. The antenna and ground connections...
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: