Sinusoidal peak detector (CB21519E)

This circuit for a frequency of 10 kHz was found in an Electronic Design. It makes use of a tunnel diode. The transistor admits equivalent.

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Sampling and holding (CB9188E)
Using components from the era, this 90's EDN circuit is used in analog to digital conversion...
Car adapter (CB7252E)
Found in an American publication from the 90s, this circuit allows the supply of 3, 6 and 9 V...
Light Controlled Monostable (CB21018E)
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