In the presence of the supply voltage of a 3 to 12 V circuit, this circuit causes the LED to pulse, at the rate of a blink every several seconds set in R3. The circuit is from a Popular Electronics from the 90s.

In the presence of the supply voltage of a 3 to 12 V circuit, this circuit causes the LED to pulse, at the rate of a blink every several seconds set in R3. The circuit is from a Popular Electronics from the 90s.