QRP VFOs
#VFO
#QRP
#oscillator
#frequency generation
#RF
#ham radio
#tuning
#signal generator
#radio circuit
#variable frequency
No description available.
Qrp-swr-bridge
The design presented is a straightforward unit intended for QRP (low-power) operation across all authorized frequencies up to 30 MHz. It utilizes a toroidal transformer (T1). The secondary winding of T1 captures a small portion of RF power, both forward...
oscillation Oscillator circuit
The first thing to understand is how capacitor C1 is related to the resonance frequency f of the circuit. It appears that selecting a frequency allows for the automatic determination of the necessary value for C1. There are uncertainties regarding...
HEE HAW ELECTRONIC SIREN
The oscillator based on IC2 generates sound, with its output linked to the base of TR1, which amplifies the signal to drive the speaker. Resistor R4 is included to limit the current through TR1 to a safe level. The oscillation...
Double oscillator metal detector
The circuit consists of two oscillators, both working at about 465 kHz. One uses an if transformer and the other uses an inductor (the search coil LI). The oscillators are coupled by a capacitor (10 pF). A beat note (produced...
The Ecology of the Oscillator Transmitter
An oscillator-only transmitter appears to be the simplest way to access the radio airwaves; however, it presents several challenges as part of a transmitting and receiving station. The issue of finding an adequate crystal-controlled transmitter for newcomers wishing to operate...
VFO circut
Building variable frequency oscillators (VFOs) in 2011 may appear to be an outdated endeavor due to the advancements in digital signal generators that feature numerous functionalities such as memory storage and audio or video frequency displays. Constructing an L-C VFO...
5W RF power amplifier
Numbered components are designated for PC-board layout purposes. C5 and C8 are disc ceramic capacitors. C6 and C7 are tantalum or electrolytic capacitors. R1, R2, and R3 are 1/4 W carbon composition resistors. Silver-mica capacitors may be substituted for polystyrene...
Quadrature-outputs-oscillator
The XR-567 operates as a precision oscillator, providing two distinct square-wave outputs at pins 5 and 8, which are nearly in quadrature phase with one another. Due to the internal biasing configuration, the typical phase shift between the two outputs...
Electronic Drum Synthesizer
The circuit consists of two twin-T oscillators set below the oscillation threshold. To initiate oscillation, a touch on the Touch Pad is required. The schematic diagram illustrates the circuit, where different touch patterns on the pads can create a variety...