We found this configuration in a 1990 Poptronics. The circuit can be powered by voltages between 6 and 15 V, changing the resistors in series with the LED. The frequency is set at R7.
This amplifier is from a May/April 1969 Popular Electronics. The components are from the period and...
This circuit may be used in IF steps of dual-conversion receivers, i.e., a type of receiver that uses...
This 555 IC circuit was found in the November 1994 issue of Radio Electronics magazine. The...