P1 on this Radio Shack circuit is a 6 V lamp with current up to 500 mA depending on Q2. The frequency is given by C1 which can have a modern standard value such as 3.3 uF or even 4.7 uF.
This circuit is from old documentation. It shows how to implement the voltage adjustments of an...
This circuit offers excellent sound quality for headphones of 150 ohms or more. The circuit was...
This circuit was found in an American documentation of the 90s. Optical resources with the LDR as a...