These optical relays, which can act as a shield, were found in an American documentation from the 1980s. The circuit has a LDR sensor. It can be adapted for other types of sensors.
The values of R and C are fixed so that a time constant of the same order of magnitude as the...
This transmitter for the 7 MHz range, as we can assume by the number of turns of the coil, since the...
The presented circuit provides an output voltage proportional to the input current, according to...