We found this circuit in an Electronics Now magazine from June 1995. The transformer has a primary according to the network and a secondary of 6 to 9 V with 100 mA.
In the figure we have the basic configuration of an operational amplifier for audio signals. The...
This General Electric circuit produces pulses of light only when light stops shining on the...
Found in an Electronic Design of 1964 this circuit has a control for the frequency and another for the...