This circuit was obtained from HAM Radio magazine in an 80's issue. The FETs are types of the time and the frequency is determined by the crystal. The circuit operates at voltages from 3 to 9 V.
Although the TDA1023 integrated circuit is no longer very common in our market, it can be used in...
This car anti-theft circuit is from a Radio Electronics magazine from May 1986. The circuit...
In the figure we have the way to activate a red LED that needs 1.7 V or even others with higher...