Found in a 90’s Popular Electronics, this circuit generates sinusoidal signals with frequency controlled by an input signal. C4, C3 and C1 together with R12 and R3 determine the frequency generated.
Suitable for battery powered microcontrolled applications this Texas Instruments circuit from its...
This amplifier with the LM1098 and LM101 by Motorola from a 1990 manual can be designed with more...
Found in a 1967 Ferranti documentation, this circuit uses a LDR from that time as a sensor....