This can be considered a complete laboratory for the repair professional. A full featured signal tracer with 13 tubes. The circuit is from the March 1946 issue of Radio Craft.
This tube circuit is from an 80's documentation. The filter is of the selective type and the...
This circuit is from a 1969 RE Experimenters Handbook. The circuit is powered by the voltage of the...
With an 18 V input, this regulator was found in Philips documentation from the 60's. The...