What is Zener voltage `( V_(2))` and how will a Zener diode be connected in circuits generally ?

How are electric devices connected in circuits ?

How do household electrical appliancess connect in circuit ?

In lab, how do you connect an ammeter to the circuit ?

(A) : Voltmeter put across a part of the circuit, it reads slightly less than the original voltage. (R) : Voltmeter is always connected in parallel in circuit across which voltage is to be measured.

In which bias can be a Zener diode be used as voltage regulator ?