Crystals usually operate at fundamental frequencies up to about 15 MHz. Whenever higher frequencies are required a frequency multiplier is placed after the crystal oscillator. The resulting... Read more
In the LT1567 Linear Technology (www.linear-tech.com/ pdf/1567i.pdf) has produced a component specially developed for building analog filters with cutoff frequencies up to 5 MHz. It contains... Read more
Ronja is the author’s dog, a beagle-mongrel, who seems increasingly often to need to be called to heel either with a shout or with a whistle. And so the idea came about for an electronic dog... Read more
In Fall or Spring, the weather may be warm enough that we’d like to save money by shutting down the main heating system in our home and just use supplementary heating based on one or more el... Read more
From what’s written on the cover of Bert van Dam’s book entitled “50 New Applications for PIC Microcontrollers” [1], some of you might think that the projects, which address programming 16/1... Read more
This square wave generator and tester is based on audio amplifier chip type TBA820M. It is presented as a design idea for further refinement and optimizing of component values by way of expe... Read more
The author repeatedly needed several different digital signals for testing his circuits, and a simple function generator did not provide a satisfactory solution. He quickly developed a desig... Read more
The compact circuit presented here is perfect for receiving the signals from pulsed fixed frequency transmitters. Chest straps from several well-known brands (Polar, Huger, Kettler, Crane, O... Read more
Crystal filters are often used for IF filters in receivers, where the bandwidth of this filter largely determines the selectivity of the receiver. The unique feature of the filter described... Read more
This circuit is for a superheterodyne receiver where the image frequency is suppressed without the use of an input filter. Instead, it uses two NE(SA)612 type mixer ICs that each work 90° ou... Read more
