This circuit was found in a 1980s documentation. The circuit uses common components having an output of 10 Hz per centigrade degree of variation. The sensor is a transistor.
This circuit generates noise pulses for audio equipment probes. The circuit is from a 90’s 303...
This modulated light transmitter was found in a 90s Popular Electronics. In place of the lamp with...
This circuit, found in a 1958 magazine, is for reference only, since the components are not easy...