Suggested by General Electric in a 1970 documentation, this circuit makes use of some components of the time, in the case of transistors. The circuit detects smoke by the transparency changing of the air.
This small source is suitable for low consumption equipment that uses batteries. The circuit is...
This interesting circuit was found in an Argentinean Radio Chassis Television magazine from March...
This circuit is from an 80's documentation, firing when the input voltage exceeds 5 V. The SCR can...