This circuit is from an American 80's documentation. The circuit indicates when the voltage of a 9 V battery drops below 7 V. The transistors can be BC548.
We found this circuit in a Japanese documentation from the 1960s. The frequency depends on the...
According to its author, this device indicates the amount of force applied to the sensors. The...
The consumption of this circuit is only 50 uA in the standby condition and 4.5 mA when supplying a pulse...