Tone Oscillator (CB22066E)

Found in old documentation, this oscillator with the LM380 produces an audio tone in a speaker. Frequency is set in VR1.

3.5 V x 10 mA Power Supply (CB13353E)
This common configuration source with diode bridge and single winding transformer was found in a...
Four Way Call Warning Light (CB17693E)
This 2009 circuit is a bilateral call warning. Easy to build, using light communication between two...
Square oscillator (CB8452E)
This circuit was found in a 90s Popular Electronics. The integrated circuit used is similar to the 741....