I cheated here because I did not have one on hand and tested the circuit with a standard non-latching relay type. It is permissible to use a 5V relay on 9V because the coil impulse lasts for only 80mS ...

Few realize how close an optical coupler resembles a relay. It is so close, in fact, that one can be wired as a Run-Stop latch circuit. One advantage over the relay is that it may be turned off via a ...

If you search the various distributor offerings, there are about 70 different models of this type relay at coil voltages from 4.5 to 24 V dc, made by four manufacturers, and costing between $3 and ...