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
In microcontroller circuits, quartz crystals provide the highest accuracy for keeping everything on frequency. With frequency and time measurement (and for commissioning master clocks) fine... Read more
This RJ-45 cable tester automatically checks cable continuity and tests the connection configuration. Each of the eight connections is checked independently and short-circuits are detected.... Read more
In the decoder designed for the DTMF Link project, a Holtek HT9170B does the main job. The natural counterpart of the HT9200B used in the associated encoder (described elsewhere in this publ... Read more
This circuit has been designed to respond only to two hand claps which occur in (relatively) quick succession and to ignore one hand clap or even continuous clapping, as well as most other s... Read more
