Paranormal phenomenon, extraterrestrial influences or simply a mental case? Who can answer? In this adventure of Prof. Ventura, Bart and Carke, the reader will get to know how a great problem, which shook this small town for a few days, was settled with the help of electronics or at least its basics, answering to some intriguing questions which scared everybody...
This transmitter has a power output stage which, using common transistors reaches close to 2 watts. With a good external antenna, this power means a range of some tens of kilometers, depending of course on the topography and the sensitivity of the receivers used.
This ultra-simple circuit detects imperceptible variations in skin resistance. With attention during an interrogation we can check if someone is lying or telling the truth.
Polygraphs, or lie detectors, work based on the small variations in skin resistance, indicated by an instrument, that occur when a person lies. Our circuit is very simple and sensitive, using a VU meter of 200 µA as a detector.
Some say that the electronics can do everything. However, when they are used to create special effects the consequences can be unexpected. Ultrasounds cause discomfort in mice and in some other animals chasing them out; musical sounds are pleasing to our ears, and there are even low frequency sounds which cause nausea being able to shake the foundations of buildings! The so-called Brown noise (see the end of the text for explanation) is an example of sound which can have disastrous effects on the human body. In an attempt to scare birds from the main square of the city, Professor Ventura, Bart and Clarke went further, using the fabulous electronic resources, and they ended up creating strange ultrasonic beats. From their powerful oscillator were generated sound vibrations with unexpected organic effects responsible for a huge mess! This story tells us what happened when Professor Ventura’s Dysenteric Oscillator went into action in the main square of the city.
Ghosts? Spirits? Extraterrestrial Beings? Sounds of the past? What would be the true origin of the sounds that wander in the mysterious currents induced on the earth? If you like to experience "beyond imagination", we give you the opportunity to penetrate both mysterious and fantastic fields.
This ultra-simple radio, for the medium wave range, does not need batteries or any other power source. The energy comes from the very radio waves that are picked up. An excellent project for STEMers.
12 V Monitor (CB859E)
If the input voltage falls below 12 V the LED glows up. Other voltages can be monitored by...
Dynamic Microphone Preamplifier (CB858E)
This circuit is suitable for low impedance m icrophones. Gain is given by the 2M2 resistor. This...
Triac and UJT Dimmer (CB857E)
This high power dimmer uses a unijunction transistor to trigger the triac. The triac is choosen...
Universal AC Motor Control (CB855E)
This control is intended for 110 VAC or 220 VAC Motors. Any TIC series triac can be used according the power...
4093 Oscillator (MSB0125E)
This oscillator can run in frequencies up 10 MHz depending on the Power supply voltage. The 1 µF...
Decade Counter (MSB124E)
This one-digit counter is part f the samples bench of the MultiSIM in one of its versions. The...
Simple Timer Using the 555 (MSB123E)
This simple timer can be used in many applications such as egg timer. The LED glows up when S1 is...
Ultrasound Emitter (MSB122E)
The circuit shown by the figure below can produce signals in the range between 20 kHz and 30 kHz....