Very strong audio spikes in a headset can damage the ear. This circuit, from a 90s Popular Electronics cuts them, being originally indicated to operate with an integrated amplifier of the time.
We found this circuit in a 1975 publication. The circuit can be made with BC548 transistors for...
This circuit was found in the December 1992 Radio Electronics magazine. Range depends on optical...
This circuit is from the National Semiconductor CMOS manual of 1977. What this circuit does is to...