Time Delay Relay Circuit Symbol

Newer designs of time delay relays use electronic circuits with resistor capacitor rc networks to generate a time delay then energize a normal instantaneous electromechanical relay coil with the electronic circuit s output.

Time delay relay circuit symbol.

It is the symbol for representing a relay that has a time delay function for both activation deactivation. A relay is an electrically operated switch it consists of a set of input terminals for a single or multiple control signals and a set of operating contact terminals. Relays are used where it is necessary to control a circuit by an independent low power signal. The switch may have any number of contacts in multiple contact forms such as make contacts break contacts or combinations thereof.

Most of the time a small voltage or current is used to switch other voltages or higher currents that may be electromechanical or fully electronic type. A special class of electromechanical relays called time delay relays provide delayed action either upon power up or power down and are commonly denoted in ladder logic diagrams by td or tr designations near the coil symbols and arrows on the contact symbols. On delay contact symbol. The relay are switching devices activated by signals.

On delay timer coils are represented like all loads illustrated ladder diagrams except there is a label with the abbreviation of td which stands for time delay and the contacts are drawn like a single pole switch with two legs coming out of the bottom as seen in figure 1. The contacts of such relays turns on off with adjustable time delay to provide pulses of power. Flashing light are prime example of time delay relay applications.