This circuit was found in RCA documentation from the 1980s. The circuit uses LDRs of the time and the 50 uA instrument has zero in the center. R1 and R2 may have 2k2 and R3 10k typically.
We found this circuit in an American documentation. The employed components are common and the...
Exciting buzzers we have the circuit of the figure, which has a modulator by interruption, with a...
This amplifier provides 7 W x 16V output and 10 W with 20 V in load of 4 ohms. At 8 ohms the power...