This circuit is from a documentation on the MC1539 from Motorola and may, however, be implemented with equivalent operations. The transistor also supports equivalent.
We found this circuit in an old Mullard (Philips) documentation. The sensor consists of a...
In the figure we have an interface using an optical coupler and the comparator LM339 or any...
This circuit may be modulated by a very low frequency signal, for example to obtain the vibrato...