This Linear Technology circuit can measure currents from 100 pA to 100 uA. The circuit is from the 80's, using a component of the era. Transistors are general purpose types.
Other series amplifiers such as the MC3301, MC3401 and LM2900 can be used on this circuit. We...
The division by eight using the 4018 is made as shown here. It isn't necessary to use additional...
We found this circuit in a Popular Electronics of the 90s. The circuit still uses light bulbs, but...