This circuit is from Motorola documentation, but can be implemented with virtually any phototransistor and any general-purpose transistor. The supply voltage can also be changed.
This non-inverting AC amplifier was found on a Popular Electronics. The setting applies to any...
This small inverter came out in an Argentine magazine from the 1970s. It can also be assembled with...
The figure shows how to use a CMOS amplifier as a crystal-controlled oscillator. The circuit is...