How to measure the quality of circuit board relays? How to wire it?

How to measure the quality of circuit board relays？
1. Measure with a multimeter. You can measure the resistance of the relay coil with a multimeter r×10ω to determine whether there is an open circuit in the coil. The resistance of the relay coil is closely related to its working voltage and current, and its working voltage and current can be calculated from the resistance of the coil.

2. Measure the contact resistance. Use the resistance gear of the multimeter to measure the resistance of the normally closed contact and the moving point, and the resistance should be 0. If the resistance is large or unstable, the contact is poor; the resistance of the normally open contact and the moving point is infinite. If there is resistance, it is contact adhesion. From this, it can be distinguished which is the normally closed contact and which is the normally open contact, and whether the relay is in good condition.

3. Measure the pull-in voltage and pull-in current. Input a set of voltages to the relay with an adjustable regulated power supply and an ammeter, and connect the ammeter to the power loop for monitoring. Slowly increase the supply voltage and record the pull-in voltage and current when you hear the relay's pull-in sound.

How to connect circuit board relay
1. Four-corner relay
To use ABCD to describe its four sides, at this time, make sure that it has two sides that belong to the control angle. If B and A are control angles, connect A with the positive line of the switch, connect B with the negative line, C with the positive line, and D with the positive line. It is connected to the control element.

2. Triangular relay
One port of the circuit board relay should be connected to the load, the other port should be connected to the power supply, this is a public port, and the other port should be connected to the button.