This circuit was found in a 90s Popular Electronics. The circuit uses 4 bicolor LEDs to indicate signals of both TTL and CMOS logic. The circuit is powered by the source of the circuit under test.
I got this circuit from an English magazine from 1977. It can still be easily assembled, as the...
The configuration shown allows to obtain a high voltage gain for FETs. FETs can be BF245 or...
This circuit controls a heating element using a triac. Triac must be fitted with a heat sink. We...