Intercom with telephone (CB7829E)

Old phones with dials can be used in a simple home intercom system, as this circuit from Popular Electronics from the 90's shows.

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Low Drift Sampling and Hold (CB5954E)
This low drift or offset circuit is from an 80's documentation. The configuration can be made with...
Precision Half Wave Rectifier (CB11228E)
This circuit rectifies low voltage sinusoidal signals for measurement purposes, as the circuit is of low...
RIAA Equalizing Preamplifier (CB4947E)
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