Basic RF Oscillator #1 - This circuit switches a relay at dark via a Light Dependent Resistor or LDR for short. The applications are numerous. In my application, it switches on a light with an older type movement sensor and is mounted on the top corner of my workshop with the LDR facing upwards. The Dark Activated Relay prevents that the light is triggered during daylight hours. But, it can also be used to switch led-beacon lights for your driveway, or whatever __ Designed by Tony van Roon VA3AVR CMOS
Inverter Parallel LC Oscillator - I have used this parallel resonant LC oscillator circuit countless times. The oscillator frequency is determined by the inductor and capacitor values. I have shown an adjustable inductor to make it easy to set the frequency to a specific value. . . Circuit by David Johnson P.E.-March, 2002
Digital Radio Mondiale (DRM) - Modification of my Yaesu FT-897 transceiver and building of a 467 kHz IF mixer to make a complete working DRM receiver system (made in the beginning of 2005) __ Designed by Bjarke Korsgaard
DSP-10 transceiver project - DSP-based 2m transceiver controlled by a Personal Computer (made in June 2001) __ Designed by Bjarke Korsgaard
Inductive Pulse Receiver (175Khz) - This circuit is discussed in more detail in the Experimenters Journal. The receiver’s six inch diameter coil detects the ring signal from the above transmitter and use a single NPN transistor to provided enough amplification for the signal to be easily viewed on an oscilloscope . . . Hobby Circuit designed by David Johnson P.E.-June, 2000
Op-Amp Oscillators Simplify RF Design - 10/10/96 EDN-Design Ideas - Figure 1 shows a novel circuit that uses a low-cost, high-speed op amp as a crystal-controlled RF sine-wave oscillator. An op-amp oscillator offers several advantages. Because an op amp is a complete amplifier with a high-impedance input Design by Charles Kitchin, Analog Devices, Wilmington, MA
Parallel LC Oscillator with CMOS
Inverter - I have used this parallel resonant LC oscillator circuit countless times. The oscillator frequency is determined by the inductor and capacitor values. I have shown an adjustable inductor to make it easy to set the frequency to a specific value . . . Hobby Circuit designed by Dave Johnson P.E.-March, 2002
PSK Meter (updated 4'th of October 2005) - PSK-Meter is a controller board to prevent overload of a transmitted PSK-signal at the HF-bands (made in February 2004) __ Designed by Bjarke Korsgaard
RF oscillator uses current-feedback op Amp - 10/03/02 EDN-Design Ideas - A current-feedback amplifier is a well-known component with many uses. Its basic block diagram shows that its input stage is a voltage follower—in practice, a symmetrical emitter follower (Figure 1). The configuration samples the output current, converts it to voltage across a large impedance, and amplifies it to the output using a high-power, low-output-impedance amplifier Design by Victor Koren, Tioga Technologies Ltd, Tel Aviv, Israel
Signal Frequency Beat Frequency Oscillator - Timing and oscillator circuit diagrams / circuit schematics __ Designed by Peter Parker VK3YE
Supporter for my fiber glass antenna mast - This is my Homebrewed fiber glass antenna mast supporter used for a 10 meter tall fiber glass antenna mast (made in May 2005) __ Designed by Bjarke Korsgaard
Yaesu FT-897, FT-857 & FT-817 transceiver-PC interface (YFPI) - This interface is used to fully control a transceiver, from a personal computer, when operating digital amateur radio modes (made in January 2006) __ Designed by Bjarke Korsgaard |