Suggested by Radio Electronics from the 90s, this circuit is suitable for NiCAd batteries with a low battery indicator and a charge indicator.
This circuit, from a 1973 documentation, can be made with BC549 transistors. The frequency depends on...
Found in a Philips documentation from the 90s, this circuit uses transistors from that time....
This circuit has a logarithmic response sourcing signals to na analog meter. The meter is a 200 µA or...