Sensor for heart monitor (CB21075E)

We found this heart rate sensor circuit in a Popular Electronics from the 90s. The placement of the emitter and the receiver is important.

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Printer Error Alarm (CB6519E
) This circuit was found in a 80’s Popular Electronics. It issues a warning signal with the signal...
13.8 V x 8 A Regulator (CB12753E)
This circuit is ideal for creating a source that allows the use of automotive power devices on a...
Motor Control with Feedback Using Triac (CB13806E)
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