ULF bass reflex on one first transistor. Numerous calculations and experiments to create powerful high-quality low-frequency amplifier has led me to believe that the most promising way to the design is to use a phase inverter on one first transistor. It is curious that such amplifiers could be forty years ago, but this has not happened due to a number of reasons.
Devices helpers
TWO BIRDS WITH ONE STONE
For several years Samsung cell phones are available with the new universal (multi-function) mini-connector. Compact and flat (see photo), it provides charging from the adapter, connecting headphones, connecting to USB port of personal computer (“data cable”) to operate the phone as a modem and many other features.
OUT, BUT NOT IMMEDIATELY
One of the inconveniences in the design of many cars is that the interior light goes out immediately when closing the doors. There are, however, a special device to delay the power light on 5-15 that the driver had time to explore the dashboard controls and to insert the ignition key. But these developments are usually complex and expensive. And reliability often leaves much to be desired.
NOT THROWN AWAY BUT USED!
The so-called “mouse” is an integral part of a modern computer. With the advent of new, old, still working, but outdated morally, as a rule, thrown away or gathering dust idle in the pantry. However, they can be used practically without changing the electronics. Make it a snap.
VOLTAGE CONVERTER
On occasion purchased a portable led flashlight in China with the battery inside. The flashlight has the ability to switch between a cluster of eight super-bright LEDs and a krypton bulb for a voltage of 5.4 V. Inside there is also a charger for the battery. In addition, the lamp is combined with a lamp – a fluorescent light with a power of 6W, powered by using a special voltage Converter 150 – 6th Century
AND UNDER THE EARTH WILL FIND
I have developed a detector has not yet been applied in peacekeeping operations to identify and neutralize minefields, no large scale geological or archaeological surveys. Not intended for professionals, and enthusiasts, whose desire to “look underground” is able to meet the design parameters listed in the table, it is an improved version of “metal detector on the beat”.
WELDING MACHINE FROM LATER
Sure: from a compact and yet sufficiently reliable, cheap and simple to manufacture “svarochnik” no workman, Thrifty, the owner will not refuse. Especially if he knew that at the heart of this machine is easily upgradable 9-ampere (familiar to almost everyone from school physics lessons) laboratory autotransformer ЛАТР2 Yes homemade mineralwater with thyristor rectifier bridge. They allow not only to safely connect to domestic lighting AC voltage of 220 V. but to change u on the electrode, and means to select the desired value of welding current.
A DAY ON THE WATER SHAKES THE NIGHT HOUSE GUARDS
I designed the machine addressed to the farmers and owners of summer houses with auxiliary water supply system, key units of which are a water source (river, lake, well or borehole), water tank electric pump Yes. From analogues this development is characterized in that in addition to performing its main function — control the electric pump makes it quite successfully solve tasks of protection of objects. This unusual flexibility is achieved not by complexity of an electrical circuit device, and by quick-change sensors, which are not only submersible multi-level electrodes and photoresists or thin, working on the rupture of the wire.
COLD CONTROL IC
In refrigerators with mechanical regulator temperature measured on the evaporator. It happens that the evaporator becomes covered with frost, and the thermostat begins to operate with an error, making failures in work of all lagoapraia. To combat this unwanted phenomenon (including — with the advent of frost) refrigerator has to periodically disable. In some designs there is a semi-automatic defrost mode, which the system is embedded a heating element with the corresponding button.
BATTERIES – ADAPTER
Today, any manufactured device can be supplemented, adapted to the specific household needs of Amateur radio and give the device a seemingly non-core second life.
For example, a widespread audible alarm, the appearance of which is shown in the photo, has excellent opportunities at low cost and small size.
