This circuit supplies a load at SO1 when the load at SO2 is powered. The circuit is from a Popular Electronics from the 90s. Diodes and triacs must match the loads.
This conventional astable multivibrator circuit with operational amplifier can be found elsewhere on...
The LDO series (Low Dropout) TPS80 from Texas Instruments (www.ti.com) can provide output voltages...
This circuit was found in a Hands On Electronics from the 80's. The circuit emits an audible alert...