If you were in a situation when you need to put expensive stuff on display, but to ensure its safety without attracting the attention of people even when triggered the alarm. Or, for example, you need to Wake up early, but not to disturb the household. This is especially true when in the same room with their parents children sleep. For this fit, we offer vibrating alarm. You can make yourself using simple electric circuit and the miniature motor with an eccentric, taken from old, obsolete cell phone.
Research scientists and experience of beekeepers show that with a good supply of benign feed and caring the contents of a winged honey bee plants can stand the winter even when severe frosts. After all trouble for weakened bee colonies in the cold season is not so much the reduced temperature, how much humidity, when the frames and the inner surface of hives moldy, and the increase of the thermal conductivity of moist air surrounding a ball of bees, and damp walls threatens to increase in heat loss with all the ensuing grave consequences.
The soldering iron is any homebrew. But those who have to deal with modern electro – and radio equipment, this tool is something special. And the requirements for it are quite hard: with small size, low supply voltage and low power consumption to ensure the excellent quality of soldering. And with the maximum comfort, including temperature controller soldering tip and a stand with a tray under flux solder and tinning.
Buying a player up to accommodate for his food during his frequent touring on-Board generator. As the adapter decided to use a homemade solid state rectifier. The implementation of the ideas started by selecting a circuit diagram of the valve half-wave diode with a smoothing capacitor. Soon he was convinced regular Wellenreiter power 3-5,4 W and an output voltage of 6-7 V and the modified on-Board power grid using a rectifier for key any diode average power and capacitor µf 500-2200 quite cope with the new task. In the end, the player was to receive a 3-volt power supply when the Bicycle is moving at a speed exceeding 10 km/h with the included headlight and not less than 8 km/h is de-energized.
Among the variety of flashing Christmas lights increasingly popular get the “ultra simple”, consisting… only of the LEDs. Instead of the usual piles of circuit design (with electronic keys, which are intermittently open-closed low-frequency RC, RL or LC oscillators) here compact semiconductor light emitter. However, the LEDs acting as a kind of microswitches, not simple (Fig. 1A—1 b). The name of this class of optoelectronic devices, developed at the junction of integrated microelectronics and optics — Blinking LED lamps (flashing LEDs, or MSV).