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.
Obtained from a 1996 documentation, this circuit uses common components and has a voltage gain of 200...
In the figure we have the conventional configuration to use a triac to control a power load from...
Found in an Electronic Design, this circuit makes use of general-purpose bipolar transistors. The circuit...