Multi-band operation requires a multi-ganged capacitor (or plug-in coils) but a very decent single band receiver can be built using any single gang variable capacitor with a maximum capacitance of 200 to 400pF. If an air variable with a maximum capacitance over 200pF is used, the receiver will have more critical tuning, as more frequency range ...
The amount of regeneration control will also vary with the type of variable capacitor used. Many air variables may be substituted as long as the minimum capacitance is somewhere around 10-20pF and the maximum capacitance (with all gangs tied together) is 100pF or more.
In most variable capacitors, the shaft is connected to one of the terminals, ensure that this is the terminal connected to ground. Otherwise, the tuning will be affected by hand capacitance, making the radio very hard to use. The coils should be wound on a form of around 2 in / 4 cm such as a toilet paper roll or PVC pipe.
The design concept of a regenerative receiver using a capacitive feedback path back into the grid tank is well known because is was used in the first regenerative receiver design patented by E.H. Armstrong in 1913.
Most intriguing with capacitive feedback is the issue of exercising feedback control. Since the internal plate to grid capacitance of the triode in use cannot be altered, feedback control needs to be implemented by an adjustable tuned plate tank in the regenerative RF amplifier stage.
The series LC tank, in contrast, offers a very fine-grained feedback control with less detuning but there may be circumstances where it might not have enough positive feedback reserves. The regenerative receiver has been the prevalent circuit for radio receivers for many years in the early history of wireless communications.
It’s still not the highest performance receiver in the world, but it’s astoundingly simple and in the early years of the 20th century it offered a huge improvement over the much simpler tuned radio frequency (TRF) receivers that were the order of the day. Armstrong’s regenerative receiver circuit. Chetvorno [CC0], via Wikimedia Commons.
Multi-band operation requires a multi-ganged capacitor (or plug-in coils) but a very decent single band receiver can be built using any single gang variable capacitor with a maximum capacitance of 200 to 400pF. If an air variable with a maximum capacitance over 200pF is used, the receiver will have more critical tuning, as more frequency range ...
The regenerative receiver is really just a crystal radio with an amplifier feeding RF back into the tank circuit. This compensates for lost energy, giving the radio an arbitrarily high Q factor and gain. Part list: 200 pF variable capacitor. 30 pF variable capacitor. This can be replaced with a 30 pF fixed cap, see the coil winding ...
For tuning, I discovered that by eliminating the scaling capacitors from the original design the variable capacitor from Uxcell could then be used without having to change the winding dimensions of the air core tuning inductor. Last, I added …
The coupling adjustment became a small variable capacitor in later designs, and this could be found as a regeneration control on the front panel of a typical receiver. At every retune to a...
Parts list for the short wave regenerative radio receiver project C1: 0.1 uF ceramic disc capacitor, 16V or higher. C2, C7, C11, C12, C15, C16, : all 0.01 uF ceramic disc capacitor, 16V or higher. C3a, C3b: Receiving type variable capacitor with one or more gangs. Minimum capacitance should be approx. 10pF
charges dc link capacitors of the variable frequency drives. The regenerative converter converts the Dc voltage in to AC and returns stored energy in the dc capacitors to the grid. Size of Variable Frequency Drives will vary according to the power ratings thereby the size of regenerative converters will vary according to drive size, Regenerative Power and Duty Ratio. voltage link …
the point in the circuit where the inductor and the variable capacitor meet, while it''s negative terminal is grounded. In fact, early sketches by Armstrong of his regenerative receiver showed such a setup [5] 3. 3This setup is, of course, prone to …
The coupling adjustment became a small variable capacitor in later designs, and this could be found as a regeneration control on the front panel of a typical receiver. At every retune to a...
This description shows how to build the RX on Veroboard as in the original EA article. The regeneration is controlled by a variable capacitor, that is difficult to obtain. Bu looking at the design with a pot for regen it is easy to combine this feature on Veroboard. You could also leave this out completely as in the original design.
For a variable capacitor to cover a complete frequency range for a given coil inductance, the rf circuit''s loading capacitance has to be small in comparison to the minimum of the variable capacitor. In a broadcast band circuit, the inductance of the resonating coil would be chosen such that the 365 mmf variable capacitance fully closed (maximum capacitance) …
regenerative and super-regenerative receivers, the superheterodyne receiver and FM modulation. Back in the 1930s impoverished hams often built regenerative receivers using vacuum tubes. …
Design and implement a minimalist but practically usable regenerative receiver capable of HF reception from 3-30 MHz. Analyze the key aspects of the receiver''s operation (e.g. behavior of the regenerative detector, gain and frequency …
Do-it-yourself regenerative FET receivers for SW. Based on my experiences with some replicas of the RIM Trabant KM, I undertook various attempts to solve the specific problems of …
Trimmer capacitors, also known as variable capacitors or trimmer capacitors, are used for fine-tuning the capacitance value in electronic circuits. They consist of two or more plates separated by a dielectric material, with the capacitance value adjusted by rotating a screw or applying voltage. Trimmer capacitors are commonly used in radio frequency (RF) circuits, …
If you aren''t familiar with the basic design -- grid lead detector, "tickler" feedback and regeneration control with a variable capacitor, look this up. Actually, Armstrong''s original circuit was slightly …
Multi-band operation requires a multi-ganged capacitor (or plug-in coils) but a very decent single band receiver can be built using any single gang variable capacitor with a maximum …
A BIPOLAR REGENERATIVE RECEIVER. Contrary to what some radio experimenters think, a bipolar regenerative design can be made to work efficiently. The major concern is the low input impedance of the detector-amplifier bipolar stage. Nevertheless, it can be easily compensated with positive feedback or regeneration. A sufficient amount of ...
This page features variable capacitors for sale. Peebles Originals; Home; Order; Kits; Catalog; Previous Page; Next Page; Variable Capacitors. 410pF (365)Air Variable Capacitor. The 410pF variable capacitor is based on the time proven 365pF variable capacitors. The extra capacitance insures easy band edge to band edge coverage. The front panel mounting holes are directly …
A BIPOLAR REGENERATIVE RECEIVER. Contrary to what some radio experimenters think, a bipolar regenerative design can be made to work efficiently. The major concern is the low input impedance of the detector …
Download scientific diagram | Regenerative harvester (a) Operation of a regenerative electrostatic harvester, (b) Charge-voltage diagram of the variable capacitor in the harvester with capacitive ...
Design and implement a minimalist but practically usable regenerative receiver capable of HF reception from 3-30 MHz. Analyze the key aspects of the receiver''s operation (e.g. behavior of the regenerative detector, gain and frequency response of the AF amplifier) using the circuit simulation tool LTspice.
[QRP Gaijin] likes to build regenerative receivers. If you''ve ever built a serious one, you know there are (at least) two problems: One is you need a variable capacitor (hard to find these days).
analyze the behavior of regenerative RF amplifier stages based on capacitive feedback for both of these by deriving equations valid for an arbitrary LC network in the plate circuit.
regenerative and super-regenerative receivers, the superheterodyne receiver and FM modulation. Back in the 1930s impoverished hams often built regenerative receivers using vacuum tubes. One tube and one variable capacitor did the work of three or more expensive amplifier stages. In Chapter 14 there is a 1930s-style regenerative receiver I built ...
This description shows how to build the RX on Veroboard as in the original EA article. The regeneration is controlled by a variable capacitor, that is difficult to obtain. Bu looking at the …
If you aren''t familiar with the basic design -- grid lead detector, "tickler" feedback and regeneration control with a variable capacitor, look this up. Actually, Armstrong''s original circuit was slightly more complicated, but the scheme I''ve mentioned covers the basic design.
Do-it-yourself regenerative FET receivers for SW. Based on my experiences with some replicas of the RIM Trabant KM, I undertook various attempts to solve the specific problems of regenerative receiver circuits with bipolar transistor. Those arrangements, however, became much more complicated and less reproducible without really effecting any ...
A regenerative variable frequency drive includes an active converter connected to an inverter. The converter has a filter capacitor, an inductor, two half bridges, bus bars that connect to the inverter and bus capacitors. The converter converts single phase AC power to DC power and DC power to single phase AC power, boosts the AC power, reduces input line harmonics, maintains input …
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