This receiver uses old transistors that are equivalent to BC548 and BC558. The photo diode is of any type. The receiver can be used on a highly sensitive audio link.
Three LM158, LM258, LM358, or LM2904 operational amplifiers are used in this instrumentation amplifier....
Found in a 1969 neon lamp publication, this circuit provides two voltages under very-low currents....
The frequency of this oscillator depends on the amount of light incident on the LDR. The circuit,...