Answer / carl_ellis

A DC power supply converts it input, AC line voltage to a
regulated DC voltage output.

A relay coil can be driven by one voltage and its contacts
can operate at a different voltage so a relay coil could
operate at 230Vac, with its contacts switching 24Vdc. But
that's not 'converting' AC to DC; the relay itself requires
that those voltages be supplied to it, it can not 'convert'
AC voltage to DC voltage.

There are linear power supplies and switch mode power
supplies (SMPS).

Relay logic is the name for the use system logic consisting
of discrete relays, switches, timers and counters which are
wired point to point.

Ladder logic is the symbolic representation of the same
elements used in relay logic: relay coils for inputs, relay
contacts for outputs, contacts for switches, timers and
counters in PLC programming.

The ladder representation looks like a ladder with rails and
rungs. The rails are line power rails, the rungs have the
logic elements in parallel or series as needed.

Carl Ellis
Measure First

Answer / sajjad khan

in PLC relay use only switching device'
i think using rectification convert 230 AC to 24 VDC
use 105400 volt PF and diodes and filter copacitor 220uf35 volt copacitor and Ziner Diode 24 volt 2 watt.
it's circuite is very simple and small.

What is the purpose of bypass valve across AS valve.

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