This circuit from Popular Electronics powers a small speaker. The transistor can be of general use and the capacitors can be altered to change the sound generated.
Figure 1 shows how the 4029 can be connected to count up to 10 and also up to 18. If pin 9 is...
This circuit was found in the February 1992 issue of Radio Electronics magazine. The circuit...
This low current solenoid driver was found in an ancient American documentation. The solenoid must be...