This is a combined circuit of tone generator and preamplifier. We found it in a 1975 documentation. Operational amplifiers of that time can be replaced by modern equivalents.
This is the receiver circuit for the previous transmitter. The range of the system can reach 100...
In this game, whoever tightens the sensors, which are metal bars or spent batteries, makes the...
This circuit is from an ancient American documentation. The T-Bridge circuit determines the...