This circuit is from March 1978 Radio Electronics. The 4-digit circuit uses a period module and is battery powered. The main integrated circuits are CMOS and TLL.
The gain for this circuit is given by the ratio between R2 and R1. The circuit is suggested by...
This circuit is based on an operational amplifier that is uncommon today, but that can reach the...
We found this circuit in a Popular Electronics of the 90s. The circuit uses a touch sensor formed by...