This circuit is from an 80's documentation, firing when the input voltage exceeds 5 V. The SCR can be the TIC106 need not have a heatsink.
This circuit is from an old Mullard (Philips) manual with applications using the 555. Choosing...
This simple rhythmic light circuit uses a 110 V to 220 V transformer and can hold a good number of...
This page shows a crystal oscillator for 2 MHz. Other frequencies can be produced depending on the...