We found this circuit in an old Mullard (Philips) documentation on the 555 and 556 integrated circuit (double 555). The relay must be 12 V with contacts that support the horn current.
This small FM transmitter for short distances has a stereo multiplexer and can be used over an...
This commercial circuit of 3 transistors was found in Japanese documentation from the 1960s. The...
We found this circuit on Motorola's 1993 Linear Interface ICs. Equivalent operational amplifiers can be...