Institute Newton C. Braga

Circuit Bench

OP27 Microphone Amplifier (CB19720E)
The low-noise amplifier shown uses a rare Raytheon operational amplifier today. The circuit can be...
Voltage Regulator LM3900 (CB4043E)
This configuration makes use of an LM3900 transconductance operational amplifier. The transistor can...
Timed Sound Switch (CB16713E)
This key is turned off by a touch sensor. The time it remains active depends on capacitor Cx. The...