This circuit is from an 80's publication. It makes use of small 6 V x 50 mA incandescent lamps. The diodes can be general purpose or even 1N4002. The transformer is 6.3 V with 100 mA or more current.
This transistor circuit was found in Mullard's 1960s transistor manual. The transistors are...
This simple multimeter takes advantage of the low cost common galvanometer of 200 uA or 1 mA and...
What this circuit does is act as an automatic gain control for an automotive stereo. It increases the...