This circuit for battery powered laser diodes was found in a 1992 RE Experimenters Handbook. The circuit uses common components today.
This circuit was taken from the 1974 Ferranti transistor manual. Transistors are common types at...
This circuit monitors the current of a series of 40 V lithium battery packs connected in series....
This 1970 Philips circuit uses a mechanical counter. The circuit is triggered by a reed switch...