Found in a 1968 Ferranti documentation, this circuit can be implemented with modern equivalent semiconductors. With the indicated components the load can be a lamp up to 1 A.
This amplified circuit was found in a magazine for radio amateurs 73 of the 90s. The circuit uses an...
The circuit shown is from the 1993 Motorola Linear Interface ICs. The power source may be common...
This circuit was found at Popular Electronics. The speaker is of the greater than 100-ohm...