The HV2405E integrated circuit is not very common these days. This circuit was found in the August 1998 issue of Electronics Now magazine. The current is a few tens of milliamps.
The circuit shown, found in a 2004 documentation, allows the use of a telephone, without the...
This simple circuit needs a high gain stage to compensate for losses. It consists of a passive tone...
The time constant for this circuit found in a 1973 publication is given by R and C. The shot is...