Most existing electronic locks use power-hungry solenoids to actuate the release mechanism.
The transmitted signals or electric impulses, which on a land line are sharply defined when received, become attenuated and prolonged in the case of a long cable, and are unable to actuate the.
Connect the ohmmeter across the contacts of the switch and actuate the switch's arm several times while checking the meter reading.
The electromotive force of the coil is, however, great enough to create in these air gaps displacement currents which are of magnitude sufficient to be equivalent to the conduction current required to actuate a telephone.
At regular intervals a rotating arm on the distributor connects the five keys of each keyboard to line, thus passing the signals to the distant station, where they pass through the distributor and certain relays which repeat the currents corresponding to the depressed keys and actuate electromagnets in the receivers.
