This circuit was found in a 73 magazine for radio amateurs of the 90s. The circuit uses two types of indicators, the diodes are for general use. The power supply is 5 V.
This circuit from a 1980 publication, converts the temperature sensed by Q1 into a frequency in a...
Using 4 operational amplifiers this circuit generates 4 different tones. The circuit is from an...
This interesting circuit is for controlling a small robot that searches for a light source. The...