…The baby was cranky for a long time and finally fell asleep. A few minutes later the doorbell rings. And, of course, the baby wakes up, and now to calm his unlikely…
I propose a simple addition to the doorbell. Just say that it’s good for calls that are switched through the circuit of 220 V. Here we need a cartridge with a bulb and the switch. Everything is connected as shown in the figure. In normal mode when you press the button is actuated and a bell, and a lamp in the “quiet” — only lamp.
I. GALKIN, engineer
Recommend to read
OBJECTIVE EXAMINER
In the sixth issue of our magazine in 1974 we told about the device "Pulse" for the control of knowledge of students. Practice operating the machine created by the participants NTTM...
SO AS NOT TO CREAK
Even the most Mature person reacts to squeaky door hinges in the house is so unpleasant and irritating they sound. And if the split lubricating door hinges you can without much of a...
