This circuit with TTL compatible output was found in a 1968 US documentation. The circuit is powered by 5 V and the frequency can be changed by changing the crystal.
Static charges in objects Dan be detected by this sensitive electroscope. The meter indicates when the...
Found in Popular Electronics from the 90s, this circuit generates a 1 kHz signal. The coil is from an...
Using a 555, this configuration appears elsewhere on this site. This is from American...