…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
ELECTROSCOPE WITH INDICATION OF THE SIGN
The well-known school electroscope, which demonstrate the phenomena of electrostatics, determines only the presence of electrostatic charge. What is it, positive or negative, we can only...
PEAR IS LIGHT
To fill the tank of a car in the field — for example, from a barrel or tank of the other vehicle drivers often use a simple hose and the so-called "sucking method", creating a vacuum...
