Ultrasounds cannot be heard by humans, but they annoy small rodents and even birds that move away from where they were emitted. By installing an ultrasonic oscillator in a silo, pantry, supply closet or other location that is subject to rodent attack, we can keep them away without the need to use dangerous chemicals or traps.
This circuit can be used in its basic version as a timer for courtesy light in cars or even in the laboratory to determine the time of chemical processes. What this timer does is to keep a lamp on for an adjustable time in a pot between 0 and a few minutes. In the standby condition with the lamp off, the device's consumption is extremely low since it uses CMOS integrated circuit.
This device generates a high voltage from ordinary batteries capable of causing a good shock to anyone who touches its output. If we connect this output to any metal object we want to protect it will be electrified.
Here's a joke for you to play with your friends or visitors to your stand at a science fair. Of course, even if people are very attentive, they will certainly be surprised by the results of their experiment, especially those who are afraid of shocks.
With this circuit we can power fluorescent lamps (even those that are already too weak to work on the power grid) from a car battery. The circuit can be used for lighting trailers, tents, or even signaling. The performance is good with low power lamps but it can also be used with larger lamps.
We present a different siren circuit based on the 4046 PPL CMOS IC. This circuit, due to its low consumption and characteristics, can be used in alarm sirens, sound effects systems, toys, etc. In the original design we included the power step to excite the speaker, but this stage can be removed or modified depending on the application.
This circuit was found in a 1977 Radio Shack documentation. Its purpose is to generate 1 Hz...
When we connect the power supply of the circuit shown in the figure the capacitor is discharged and thus...
We find this circuit in an old American documentation, but it is perfectly current by its...
This circuit is from an American publication of 1978. It can be assembled with modern transistors, since...
The power source shown for powering for small TTL circuits was found on a Radio Electronics...
IGBTs are widely used in frequency inverters, power controllers, switched sources and DC/DC...
This oscillator can run in frequencies up 10 MHz depending on the Power supply voltage. The 1 µF...
This one-digit counter is part f the samples bench of the MultiSIM in one of its versions. The...