Fault indicator (CB21396E)

This circuit was found in old American documentation. The operational amplifiers are from the period, but modern equivalents can be used.

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Driver for Electric Typewriter (CB6561E)
This circuit was found in a Philips documentation from 1966. Its purpose is to drive the solenoid...
4.59 MHz XTAL Oscillator (CB13861E)
This TTL oscillator uses an old TV crystal, having been found in an American publication in 1976....
Switching Regulator 5 V x 1 A MC723 2 (CB14527E)
This is a high efficiency version with the MC723 which is the Motorola version for this well-known...